diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AbstractReadContext.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AbstractReadContext.java
index 9d687bb5168..c177f91edf0 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AbstractReadContext.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AbstractReadContext.java
@@ -794,8 +794,7 @@ CloseableIterator<PartialResultSet> startStream(@Nullable ByteString resumeToken
             return stream;
           }
         };
-    GrpcResultSet resultSet = new GrpcResultSet(stream, this);
-    return resultSet;
+    return new GrpcResultSet(stream, this);
   }
 
   private Struct consumeSingleRow(ResultSet resultSet) {
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AbstractResultSet.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AbstractResultSet.java
index 56cd1af47e9..00391447d90 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AbstractResultSet.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AbstractResultSet.java
@@ -208,7 +208,7 @@ protected com.google.protobuf.Value computeNext() {
       Object merged =
           kind == KindCase.STRING_VALUE
               ? value.getStringValue()
-              : new ArrayList<com.google.protobuf.Value>(value.getListValue().getValuesList());
+              : new ArrayList<>(value.getListValue().getValuesList());
       while (current.getChunkedValue() && pos == current.getValuesCount()) {
         if (!ensureReady(StreamValue.RESULT)) {
           throw newSpannerException(
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AsyncResultSet.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AsyncResultSet.java
index 1ae353c0027..501ae054e9f 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AsyncResultSet.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AsyncResultSet.java
@@ -39,9 +39,8 @@ enum CursorState {
    * Non-blocking call that attempts to step the cursor to the next position in the stream. The
    * cursor may be inspected only if the cursor returns {@code CursorState.OK}.
    *
-   * <p>A caller will typically call {@link #tryNext()} in a loop inside the ReadyCallback,
-   * consuming all results available. For more information see {@link #setCallback(Executor,
-   * ReadyCallback)}.
+   * <p>A caller will typically call tryNext in a loop inside the ReadyCallback, consuming all
+   * results available. For more information see {@link #setCallback(Executor, ReadyCallback)}.
    *
    * <p>Currently this method may only be called if a ReadyCallback has been registered. This is for
    * safety purposes only, and may be relaxed in future.
@@ -146,8 +145,8 @@ interface ReadyCallback {
    * <ul>
    *   <li>Semi-async: make {@code upstream.emit()} a blocking call. This will block the callback
    *       thread until progress is possible. When coding in this way the threads in the Executor
-   *       provided to {@link #setCallback(Executor, ReadyCallback)} must be blockable without
-   *       causing harm to progress in your system.
+   *       provided to setCallback must be blockable without causing harm to progress in your
+   *       system.
    *   <li>Full-async: call {@code cursor.pause()} and return from the callback with data still in
    *       the Cursor. Once in this state cursor waits until resume() is called before calling
    *       callback again.
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AsyncResultSetImpl.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AsyncResultSetImpl.java
index fd172e96f9a..88800563337 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AsyncResultSetImpl.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AsyncResultSetImpl.java
@@ -62,11 +62,11 @@ private enum State {
     /** Does this state mean that the result set should permanently stop producing rows. */
     private final boolean shouldStop;
 
-    private State() {
+    State() {
       shouldStop = false;
     }
 
-    private State(boolean shouldStop) {
+    State(boolean shouldStop) {
       this.shouldStop = shouldStop;
     }
   }
@@ -116,32 +116,31 @@ private State(boolean shouldStop) {
   private State state = State.INITIALIZED;
 
   /**
-   * {@link #finished} indicates whether all the results from the underlying result set have been
-   * read.
+   * This variable indicates whether all the results from the underlying result set have been read.
    */
   private volatile boolean finished;
 
   private volatile ApiFuture<Void> result;
 
   /**
-   * {@link #cursorReturnedDoneOrException} indicates whether {@link #tryNext()} has returned {@link
-   * CursorState#DONE} or a {@link SpannerException}.
+   * This variable indicates whether {@link #tryNext()} has returned {@link CursorState#DONE} or a
+   * {@link SpannerException}.
    */
   private volatile boolean cursorReturnedDoneOrException;
 
   /**
-   * {@link #pausedLatch} is used to pause the producer when the {@link AsyncResultSet} is paused.
-   * The production of rows that are put into the buffer is only paused once the buffer is full.
+   * This variable is used to pause the producer when the {@link AsyncResultSet} is paused. The
+   * production of rows that are put into the buffer is only paused once the buffer is full.
    */
   private volatile CountDownLatch pausedLatch = new CountDownLatch(1);
   /**
-   * {@link #bufferConsumptionLatch} is used to pause the producer when the buffer is full and the
-   * consumer needs some time to catch up.
+   * This variable is used to pause the producer when the buffer is full and the consumer needs some
+   * time to catch up.
    */
   private volatile CountDownLatch bufferConsumptionLatch = new CountDownLatch(0);
   /**
-   * {@link #consumingLatch} is used to pause the producer when all rows have been put into the
-   * buffer, but the consumer (the callback) has not yet received and processed all rows.
+   * This variable is used to pause the producer when all rows have been put into the buffer, but
+   * the consumer (the callback) has not yet received and processed all rows.
    */
   private volatile CountDownLatch consumingLatch = new CountDownLatch(0);
 
@@ -531,7 +530,7 @@ public <T> ApiFuture<List<T>> toListAsync(
       Preconditions.checkState(
           this.state == State.INITIALIZED, "This AsyncResultSet has already been used.");
       final SettableApiFuture<List<T>> res = SettableApiFuture.<List<T>>create();
-      CreateListCallback<T> callback = new CreateListCallback<T>(res, transformer);
+      CreateListCallback<T> callback = new CreateListCallback<>(res, transformer);
       ApiFuture<Void> finished = setCallback(executor, callback);
       return ApiFutures.transformAsync(
           finished,
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AsyncTransactionManager.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AsyncTransactionManager.java
index a4741dd3293..c648b567d7a 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AsyncTransactionManager.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AsyncTransactionManager.java
@@ -49,7 +49,7 @@ public interface AsyncTransactionManager extends AutoCloseable {
    * {@link ApiFuture} that returns a {@link TransactionContext} and that supports chaining of
    * multiple {@link TransactionContextFuture}s to form a transaction.
    */
-  public interface TransactionContextFuture extends ApiFuture<TransactionContext> {
+  interface TransactionContextFuture extends ApiFuture<TransactionContext> {
     /**
      * Sets the first step to execute as part of this transaction after the transaction has started
      * using the specified executor. {@link MoreExecutors#directExecutor()} can be be used for
@@ -65,7 +65,7 @@ <O> AsyncTransactionStep<Void, O> then(
    * is executed using an {@link AsyncTransactionManager}. This future is returned by the call to
    * {@link AsyncTransactionStep#commitAsync()} of the last step in the transaction.
    */
-  public interface CommitTimestampFuture extends ApiFuture<Timestamp> {
+  interface CommitTimestampFuture extends ApiFuture<Timestamp> {
     /**
      * Returns the commit timestamp of the transaction. Getting this value should always be done in
      * order to ensure that the transaction succeeded. If any of the steps in the transaction fails
@@ -125,7 +125,7 @@ Timestamp get(long timeout, TimeUnit unit)
    *         })
    * }</pre>
    */
-  public interface AsyncTransactionStep<I, O> extends ApiFuture<O> {
+  interface AsyncTransactionStep<I, O> extends ApiFuture<O> {
     /**
      * Adds a step to the transaction chain that should be executed using the specified executor.
      * This step is guaranteed to be executed only after the previous step executed successfully.
@@ -150,11 +150,11 @@ <RES> AsyncTransactionStep<O, RES> then(
    * parameters. The method should return an {@link ApiFuture} that will return the result of this
    * step.
    */
-  public interface AsyncTransactionFunction<I, O> {
+  interface AsyncTransactionFunction<I, O> {
     /**
-     * {@link #apply(TransactionContext, Object)} is called when this transaction step is executed.
-     * The input value is the result of the previous step, and this method will only be called if
-     * the previous step executed successfully.
+     * This method is called when this transaction step is executed. The input value is the result
+     * of the previous step, and this method will only be called if the previous step executed
+     * successfully.
      *
      * @param txn the {@link TransactionContext} that can be used to execute statements.
      * @param input the result of the previous transaction step.
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AsyncTransactionManagerImpl.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AsyncTransactionManagerImpl.java
index 2ec914c24aa..1d085491192 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AsyncTransactionManagerImpl.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/AsyncTransactionManagerImpl.java
@@ -79,9 +79,7 @@ public ApiFuture<Void> closeAsync() {
   @Override
   public TransactionContextFutureImpl beginAsync() {
     Preconditions.checkState(txn == null, "begin can only be called once");
-    TransactionContextFutureImpl begin =
-        new TransactionContextFutureImpl(this, internalBeginAsync(true));
-    return begin;
+    return new TransactionContextFutureImpl(this, internalBeginAsync(true));
   }
 
   private ApiFuture<TransactionContext> internalBeginAsync(boolean firstAttempt) {
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/DatabaseAdminClientImpl.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/DatabaseAdminClientImpl.java
index 6129e0fa2d0..30bb581e9a7 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/DatabaseAdminClientImpl.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/DatabaseAdminClientImpl.java
@@ -105,7 +105,7 @@ public OperationFuture<Database, RestoreDatabaseMetadata> restoreDatabase(Restor
     final OperationFuture<com.google.spanner.admin.database.v1.Database, RestoreDatabaseMetadata>
         rawOperationFuture = rpc.restoreDatabase(restore);
 
-    return new OperationFutureImpl<Database, RestoreDatabaseMetadata>(
+    return new OperationFutureImpl<>(
         rawOperationFuture.getPollingFuture(),
         rawOperationFuture.getInitialFuture(),
         new ApiFunction<OperationSnapshot, Database>() {
@@ -308,7 +308,7 @@ public OperationFuture<Database, CreateDatabaseMetadata> createDatabase(
         rawOperationFuture =
             rpc.createDatabase(
                 database.getId().getInstanceId().getName(), createStatement, statements, database);
-    return new OperationFutureImpl<Database, CreateDatabaseMetadata>(
+    return new OperationFutureImpl<>(
         rawOperationFuture.getPollingFuture(),
         rawOperationFuture.getInitialFuture(),
         new ApiFunction<OperationSnapshot, Database>() {
@@ -347,7 +347,7 @@ public OperationFuture<Void, UpdateDatabaseDdlMetadata> updateDatabaseDdl(
     final String opId = operationId != null ? operationId : randomOperationId();
     OperationFuture<Empty, UpdateDatabaseDdlMetadata> rawOperationFuture =
         rpc.updateDatabaseDdl(dbName, statements, opId);
-    return new OperationFutureImpl<Void, UpdateDatabaseDdlMetadata>(
+    return new OperationFutureImpl<>(
         rawOperationFuture.getPollingFuture(),
         rawOperationFuture.getInitialFuture(),
         new ApiFunction<OperationSnapshot, Void>() {
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/InstanceAdminClientImpl.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/InstanceAdminClientImpl.java
index 0bbaa15072f..409f9a31adf 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/InstanceAdminClientImpl.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/InstanceAdminClientImpl.java
@@ -103,7 +103,7 @@ public OperationFuture<Instance, CreateInstanceMetadata> createInstance(Instance
         rawOperationFuture =
             rpc.createInstance(projectName, instance.getId().getInstance(), instance.toProto());
 
-    return new OperationFutureImpl<Instance, CreateInstanceMetadata>(
+    return new OperationFutureImpl<>(
         rawOperationFuture.getPollingFuture(),
         rawOperationFuture.getInitialFuture(),
         new ApiFunction<OperationSnapshot, Instance>() {
@@ -172,7 +172,7 @@ public OperationFuture<Instance, UpdateInstanceMetadata> updateInstance(
 
     OperationFuture<com.google.spanner.admin.instance.v1.Instance, UpdateInstanceMetadata>
         rawOperationFuture = rpc.updateInstance(instance.toProto(), fieldMask);
-    return new OperationFutureImpl<Instance, UpdateInstanceMetadata>(
+    return new OperationFutureImpl<>(
         rawOperationFuture.getPollingFuture(),
         rawOperationFuture.getInitialFuture(),
         new ApiFunction<OperationSnapshot, Instance>() {
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/InstanceInfo.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/InstanceInfo.java
index 6908a4999ac..1892b914bb8 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/InstanceInfo.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/InstanceInfo.java
@@ -56,7 +56,7 @@ static FieldMask toFieldMask(InstanceField... fields) {
   }
 
   /** State of the Instance. */
-  public static enum State {
+  public enum State {
     UNSPECIFIED,
     CREATING,
     READY
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/Operation.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/Operation.java
index 85c6d6cc415..e7ee5e53345 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/Operation.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/Operation.java
@@ -45,7 +45,7 @@ public class Operation<R, M> {
           .setMaxRetryDelay(Duration.ofMinutes(500L))
           .build();
 
-  static interface Parser<R, M> {
+  interface Parser<R, M> {
     R parseResult(Any response);
 
     M parseMetadata(Any metadata);
@@ -85,7 +85,7 @@ private static <R, M> Operation<R, M> failed(
     SpannerException e =
         SpannerExceptionFactory.newSpannerException(
             ErrorCode.fromRpcStatus(status), status.getMessage(), null);
-    return new Operation<R, M>(rpc, name, metadata, null, e, true, parser, clock);
+    return new Operation<>(rpc, name, metadata, null, e, true, parser, clock);
   }
 
   private static <R, M> Operation<R, M> successful(
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/Options.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/Options.java
index 3d443f3673a..fa2cd2526e4 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/Options.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/Options.java
@@ -36,7 +36,7 @@ public enum RpcPriority {
 
     private final Priority proto;
 
-    private RpcPriority(Priority proto) {
+    RpcPriority(Priority proto) {
       this.proto = Preconditions.checkNotNull(proto);
     }
   }
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/ReadContext.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/ReadContext.java
index e87d40fb207..a5535ec5042 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/ReadContext.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/ReadContext.java
@@ -221,5 +221,5 @@ ApiFuture<Struct> readRowUsingIndexAsync(
 
   /** Closes this read context and frees up the underlying resources. */
   @Override
-  public void close();
+  void close();
 }
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionClient.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionClient.java
index e0f8a31a0fa..7afb896ba59 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionClient.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionClient.java
@@ -155,7 +155,7 @@ public void run() {
    * Callback interface to be used for BatchCreateSessions. When sessions become available or
    * session creation fails, one of the callback methods will be called.
    */
-  static interface SessionConsumer {
+  interface SessionConsumer {
     /** Called when a session has been created and is ready for use. */
     void onSessionReady(SessionImpl session);
 
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionImpl.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionImpl.java
index 9896b29f235..5674133c2b6 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionImpl.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionImpl.java
@@ -79,7 +79,7 @@ static void throwIfTransactionsPending() {
    * transactions, and read-write transactions. The defining characteristic is that a session may
    * only have one such transaction active at a time.
    */
-  static interface SessionTransaction {
+  interface SessionTransaction {
     /** Invalidates the transaction, generally because a new one has been started on the session. */
     void invalidate();
     /** Registers the current span on the transaction. */
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionPool.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionPool.java
index 1638567b36a..c4547c664ef 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionPool.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionPool.java
@@ -1749,9 +1749,9 @@ private void replenishPool() {
     }
   }
 
-  private static enum Position {
+  private enum Position {
     FIRST,
-    RANDOM;
+    RANDOM
   }
 
   private final SessionPoolOptions options;
@@ -2058,7 +2058,7 @@ private PooledSessionFuture checkoutSession(
       logger.log(
           Level.FINE,
           "No session available in the pool. Blocking for one to become available/created");
-      span.addAnnotation(String.format("Waiting for a session to come available"));
+      span.addAnnotation("Waiting for a session to come available");
       sessionFuture = waiter;
     } else {
       SettableFuture<PooledSession> fut = SettableFuture.create();
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionPoolOptions.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionPoolOptions.java
index 895b3fd5fbb..208c025e6da 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionPoolOptions.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionPoolOptions.java
@@ -182,19 +182,19 @@ public static Builder newBuilder() {
     return new Builder();
   }
 
-  private static enum ActionOnExhaustion {
+  private enum ActionOnExhaustion {
     BLOCK,
     FAIL,
   }
 
-  private static enum ActionOnSessionNotFound {
+  private enum ActionOnSessionNotFound {
     RETRY,
-    FAIL;
+    FAIL
   }
 
-  private static enum ActionOnSessionLeak {
+  private enum ActionOnSessionLeak {
     WARN,
-    FAIL;
+    FAIL
   }
 
   /** Builder for creating SessionPoolOptions. */
@@ -204,7 +204,7 @@ public static class Builder {
     private int maxSessions = DEFAULT_MAX_SESSIONS;
     private int incStep = DEFAULT_INC_STEP;
 
-    /** Set a higher value for {@link #minSessions} instead of using {@link #maxIdleSessions}. */
+    /** Set a higher value for {@link #minSessions} instead of using this field. */
     @Deprecated private int maxIdleSessions;
 
     /**
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SpannerExceptionFactory.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SpannerExceptionFactory.java
index 696ffc9a216..da17680d6db 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SpannerExceptionFactory.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SpannerExceptionFactory.java
@@ -270,12 +270,13 @@ static SpannerException newSpannerExceptionPreformatted(
       case NOT_FOUND:
         ResourceInfo resourceInfo = extractResourceInfo(cause);
         if (resourceInfo != null) {
-          if (resourceInfo.getResourceType().equals(SESSION_RESOURCE_TYPE)) {
-            return new SessionNotFoundException(token, message, resourceInfo, cause);
-          } else if (resourceInfo.getResourceType().equals(DATABASE_RESOURCE_TYPE)) {
-            return new DatabaseNotFoundException(token, message, resourceInfo, cause);
-          } else if (resourceInfo.getResourceType().equals(INSTANCE_RESOURCE_TYPE)) {
-            return new InstanceNotFoundException(token, message, resourceInfo, cause);
+          switch (resourceInfo.getResourceType()) {
+            case SESSION_RESOURCE_TYPE:
+              return new SessionNotFoundException(token, message, resourceInfo, cause);
+            case DATABASE_RESOURCE_TYPE:
+              return new DatabaseNotFoundException(token, message, resourceInfo, cause);
+            case INSTANCE_RESOURCE_TYPE:
+              return new InstanceNotFoundException(token, message, resourceInfo, cause);
           }
         }
         // Fall through to the default.
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SpannerImpl.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SpannerImpl.java
index 9fa8b30be28..166360efe8f 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SpannerImpl.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SpannerImpl.java
@@ -300,7 +300,7 @@ public Page<S> getNextPage() {
       for (T proto : nextPage.getResults()) {
         results.add(fromProto(proto));
       }
-      return new PageImpl<S>(this, nextPageToken, results);
+      return new PageImpl<>(this, nextPageToken, results);
     }
 
     void setNextPageToken(String nextPageToken) {
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SpannerOptions.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SpannerOptions.java
index 79ad3e9dc02..39fe0329257 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SpannerOptions.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SpannerOptions.java
@@ -127,7 +127,7 @@ public class SpannerOptions extends ServiceOptions<Spanner, SpannerOptions> {
    * Interface that can be used to provide {@link CallCredentials} instead of {@link Credentials} to
    * {@link SpannerOptions}.
    */
-  public static interface CallCredentialsProvider {
+  public interface CallCredentialsProvider {
     /** Return the {@link CallCredentials} to use for a gRPC call. */
     CallCredentials getCallCredentials();
   }
@@ -181,7 +181,7 @@ public static interface CallCredentialsProvider {
    *     }
    * }</pre>
    */
-  public static interface CallContextConfigurator {
+  public interface CallContextConfigurator {
     /**
      * Configure a {@link ApiCallContext} for a specific RPC call.
      *
@@ -472,7 +472,7 @@ public ServiceRpc create(SpannerOptions options) {
   interface CloseableExecutorProvider extends ExecutorProvider, AutoCloseable {
     /** Overridden to suppress the throws declaration of the super interface. */
     @Override
-    public void close();
+    void close();
   }
 
   static class FixedCloseableExecutorProvider implements CloseableExecutorProvider {
@@ -576,7 +576,7 @@ private SpannerOptions(Builder builder) {
    * The environment to read configuration values from. The default implementation uses environment
    * variables.
    */
-  public static interface SpannerEnvironment {
+  public interface SpannerEnvironment {
     /**
      * The optimizer version to use. Must return an empty string to indicate that no value has been
      * set.
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/TransactionManager.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/TransactionManager.java
index c9a56d8100a..68c9ea29c15 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/TransactionManager.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/TransactionManager.java
@@ -38,7 +38,7 @@
 public interface TransactionManager extends AutoCloseable {
 
   /** State of the transaction manager. */
-  public enum TransactionState {
+  enum TransactionState {
     // Transaction has been started either by calling {@link #begin()} or via
     // {@link resetForRetry()} but has not been commited or rolled back yet.
     STARTED,
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/AbstractBaseUnitOfWork.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/AbstractBaseUnitOfWork.java
index 9ba86b3ec52..3fb3fae8e5d 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/AbstractBaseUnitOfWork.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/AbstractBaseUnitOfWork.java
@@ -77,7 +77,7 @@ public String getMessage() {
 
   enum InterceptorsUsage {
     INVOKE_INTERCEPTORS,
-    IGNORE_INTERCEPTORS;
+    IGNORE_INTERCEPTORS
   }
 
   abstract static class Builder<B extends Builder<?, T>, T extends AbstractBaseUnitOfWork> {
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/AnalyzeMode.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/AnalyzeMode.java
index be4f3da2aa3..f67d2267771 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/AnalyzeMode.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/AnalyzeMode.java
@@ -30,7 +30,7 @@ enum AnalyzeMode {
 
   private final QueryAnalyzeMode mode;
 
-  private AnalyzeMode(QueryAnalyzeMode mode) {
+  AnalyzeMode(QueryAnalyzeMode mode) {
     this.mode = mode;
   }
 
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/AutocommitDmlMode.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/AutocommitDmlMode.java
index e5f4cc7446b..8710bdd01d1 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/AutocommitDmlMode.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/AutocommitDmlMode.java
@@ -23,7 +23,7 @@ public enum AutocommitDmlMode {
 
   private final String statementString;
 
-  private AutocommitDmlMode() {
+  AutocommitDmlMode() {
     this.statementString = name();
   }
 
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/ClientSideStatementValueConverters.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/ClientSideStatementValueConverters.java
index 40fbb78d806..8dd0a10a4dc 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/ClientSideStatementValueConverters.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/ClientSideStatementValueConverters.java
@@ -114,7 +114,7 @@ public Duration convert(String value) {
         } else {
           Duration duration =
               ReadOnlyStalenessUtil.createDuration(
-                  Long.valueOf(matcher.group(1)),
+                  Long.parseLong(matcher.group(1)),
                   ReadOnlyStalenessUtil.parseTimeUnit(matcher.group(2)));
           if (duration.getSeconds() == 0L && duration.getNanos() == 0) {
             return null;
@@ -171,7 +171,7 @@ public TimestampBound convert(String value) {
           case EXACT_STALENESS:
             try {
               return TimestampBound.ofExactStaleness(
-                  Long.valueOf(matcher.group(groupIndex + 2)),
+                  Long.parseLong(matcher.group(groupIndex + 2)),
                   ReadOnlyStalenessUtil.parseTimeUnit(matcher.group(groupIndex + 3)));
             } catch (IllegalArgumentException e) {
               throw SpannerExceptionFactory.newSpannerException(
@@ -180,7 +180,7 @@ public TimestampBound convert(String value) {
           case MAX_STALENESS:
             try {
               return TimestampBound.ofMaxStaleness(
-                  Long.valueOf(matcher.group(groupIndex + 2)),
+                  Long.parseLong(matcher.group(groupIndex + 2)),
                   ReadOnlyStalenessUtil.parseTimeUnit(matcher.group(groupIndex + 3)));
             } catch (IllegalArgumentException e) {
               throw SpannerExceptionFactory.newSpannerException(
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/Connection.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/Connection.java
index 4a0bcf27019..813dda25cca 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/Connection.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/Connection.java
@@ -799,13 +799,6 @@ public interface Connection extends AutoCloseable {
    */
   ResultSet executeQuery(Statement query, QueryOption... options);
 
-  /**
-   * Same as {@link #executeQuery(Statement, QueryOption...)}, but is guaranteed to be non-blocking
-   * and returns the query result as an {@link AsyncResultSet}. See {@link
-   * AsyncResultSet#setCallback(java.util.concurrent.Executor,
-   * com.google.cloud.spanner.AsyncResultSet.ReadyCallback)} for more information on how to consume
-   * the results of the query asynchronously.
-   */
   /**
    * Executes the given statement asynchronously as a query and returns the result as an {@link
    * AsyncResultSet}. This method is guaranteed to be non-blocking. If the statement does not
@@ -1011,7 +1004,7 @@ public interface Connection extends AutoCloseable {
    * <p>NOT INTENDED FOR EXTERNAL USE!
    */
   @InternalApi
-  public static final class InternalMetadataQuery implements QueryOption {
+  final class InternalMetadataQuery implements QueryOption {
     @InternalApi public static final InternalMetadataQuery INSTANCE = new InternalMetadataQuery();
 
     private InternalMetadataQuery() {}
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/ConnectionImpl.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/ConnectionImpl.java
index 851f685f6e7..138dcd12d3f 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/ConnectionImpl.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/ConnectionImpl.java
@@ -119,7 +119,7 @@ public Thread newThread(Runnable r) {
   enum BatchMode {
     NONE,
     DDL,
-    DML;
+    DML
   }
 
   /**
@@ -188,8 +188,8 @@ static UnitOfWorkType of(TransactionMode transactionMode) {
 
   private UnitOfWork currentUnitOfWork = null;
   /**
-   * The {@link ConnectionImpl#inTransaction} field is only used in autocommit mode to indicate that
-   * the user has explicitly started a transaction.
+   * This field is only used in autocommit mode to indicate that the user has explicitly started a
+   * transaction.
    */
   private boolean inTransaction = false;
   /**
@@ -667,8 +667,8 @@ public ApiFuture<Void> beginTransactionAsync() {
   }
 
   /** Internal interface for ending a transaction (commit/rollback). */
-  private static interface EndTransactionMethod {
-    public ApiFuture<Void> endAsync(UnitOfWork t);
+  private interface EndTransactionMethod {
+    ApiFuture<Void> endAsync(UnitOfWork t);
   }
 
   private static final class Commit implements EndTransactionMethod {
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/ConnectionOptions.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/ConnectionOptions.java
index 48d60d86c70..8e04494f6b9 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/ConnectionOptions.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/ConnectionOptions.java
@@ -605,25 +605,25 @@ CredentialsService getCredentialsService() {
   @VisibleForTesting
   static boolean parseUsePlainText(String uri) {
     String value = parseUriProperty(uri, USE_PLAIN_TEXT_PROPERTY_NAME);
-    return value != null ? Boolean.valueOf(value) : DEFAULT_USE_PLAIN_TEXT;
+    return value != null ? Boolean.parseBoolean(value) : DEFAULT_USE_PLAIN_TEXT;
   }
 
   @VisibleForTesting
   static boolean parseAutocommit(String uri) {
     String value = parseUriProperty(uri, AUTOCOMMIT_PROPERTY_NAME);
-    return value != null ? Boolean.valueOf(value) : DEFAULT_AUTOCOMMIT;
+    return value != null ? Boolean.parseBoolean(value) : DEFAULT_AUTOCOMMIT;
   }
 
   @VisibleForTesting
   static boolean parseReadOnly(String uri) {
     String value = parseUriProperty(uri, READONLY_PROPERTY_NAME);
-    return value != null ? Boolean.valueOf(value) : DEFAULT_READONLY;
+    return value != null ? Boolean.parseBoolean(value) : DEFAULT_READONLY;
   }
 
   @VisibleForTesting
   static boolean parseRetryAbortsInternally(String uri) {
     String value = parseUriProperty(uri, RETRY_ABORTS_INTERNALLY_PROPERTY_NAME);
-    return value != null ? Boolean.valueOf(value) : DEFAULT_RETRY_ABORTS_INTERNALLY;
+    return value != null ? Boolean.parseBoolean(value) : DEFAULT_RETRY_ABORTS_INTERNALLY;
   }
 
   @VisibleForTesting
@@ -671,18 +671,18 @@ static String parseOptimizerVersion(String uri) {
   @VisibleForTesting
   static boolean parseReturnCommitStats(String uri) {
     String value = parseUriProperty(uri, "returnCommitStats");
-    return value != null ? Boolean.valueOf(value) : false;
+    return value != null ? Boolean.parseBoolean(value) : false;
   }
 
   static boolean parseAutoConfigEmulator(String uri) {
     String value = parseUriProperty(uri, "autoConfigEmulator");
-    return value != null ? Boolean.valueOf(value) : false;
+    return value != null ? Boolean.parseBoolean(value) : false;
   }
 
   @VisibleForTesting
   static boolean parseLenient(String uri) {
     String value = parseUriProperty(uri, LENIENT_PROPERTY_NAME);
-    return value != null ? Boolean.valueOf(value) : DEFAULT_LENIENT;
+    return value != null ? Boolean.parseBoolean(value) : DEFAULT_LENIENT;
   }
 
   @VisibleForTesting
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/ReadOnlyStalenessUtil.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/ReadOnlyStalenessUtil.java
index de5c5cfd1ce..dd2b8612ec1 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/ReadOnlyStalenessUtil.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/ReadOnlyStalenessUtil.java
@@ -61,7 +61,7 @@ enum TimeUnitAbbreviation {
     private final String abbreviation;
     private final TimeUnit unit;
 
-    private TimeUnitAbbreviation(String abbreviation, TimeUnit unit) {
+    TimeUnitAbbreviation(String abbreviation, TimeUnit unit) {
       this.abbreviation = abbreviation;
       this.unit = unit;
     }
@@ -97,7 +97,7 @@ static TimeUnit parseTimeUnit(String unit) {
    * Internal interface that is used to generalize getting a time duration from Cloud Spanner
    * read-only staleness settings.
    */
-  static interface DurationValueGetter {
+  interface DurationValueGetter {
     long getDuration(TimeUnit unit);
 
     boolean hasDuration();
@@ -196,7 +196,7 @@ static String timestampBoundToString(TimestampBound staleness) {
    */
   static String durationToString(DurationValueGetter function) {
     TimeUnit unit = getAppropriateTimeUnit(function);
-    return String.valueOf(function.getDuration(unit)) + getTimeUnitAbbreviation(unit);
+    return function.getDuration(unit) + getTimeUnitAbbreviation(unit);
   }
 
   /**
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/SingleUseTransaction.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/SingleUseTransaction.java
index deaed9d836d..61f9bedb28e 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/SingleUseTransaction.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/SingleUseTransaction.java
@@ -205,9 +205,7 @@ public ApiFuture<ResultSet> executeQueryAsync(
           }
         };
     readTimestamp = SettableApiFuture.create();
-    ApiFuture<ResultSet> res =
-        executeStatementAsync(statement, callable, SpannerGrpc.getExecuteStreamingSqlMethod());
-    return res;
+    return executeStatementAsync(statement, callable, SpannerGrpc.getExecuteStreamingSqlMethod());
   }
 
   @Override
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/SpannerPool.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/SpannerPool.java
index 132478b364c..976f69e5934 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/SpannerPool.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/SpannerPool.java
@@ -96,7 +96,7 @@ public static void closeSpannerPool() {
   @VisibleForTesting
   enum CheckAndCloseSpannersMode {
     WARN,
-    ERROR;
+    ERROR
   }
 
   private final class CloseSpannerRunnable implements Runnable {
@@ -291,11 +291,8 @@ Spanner getSpanner(ConnectionOptions options, ConnectionImpl connection) {
         spanner = createSpanner(key, options);
         spanners.put(key, spanner);
       }
-      List<ConnectionImpl> registeredConnectionsForSpanner = connections.get(key);
-      if (registeredConnectionsForSpanner == null) {
-        registeredConnectionsForSpanner = new ArrayList<>();
-        connections.put(key, registeredConnectionsForSpanner);
-      }
+      List<ConnectionImpl> registeredConnectionsForSpanner =
+          connections.computeIfAbsent(key, k -> new ArrayList<>());
       registeredConnectionsForSpanner.add(connection);
       lastConnectionClosedAt.remove(key);
       return spanner;
@@ -484,8 +481,7 @@ void closeUnusedSpanners(
         // Check whether the last connection was closed more than
         // closeSpannerAfterMillisecondsUnused milliseconds ago.
         if (closedAt != null
-            && ((TimeUnit.MILLISECONDS.convert(ticker.read(), TimeUnit.NANOSECONDS)
-                    - closedAt.longValue()))
+            && ((TimeUnit.MILLISECONDS.convert(ticker.read(), TimeUnit.NANOSECONDS) - closedAt))
                 > closeSpannerAfterMillisecondsUnused) {
           Spanner spanner = spanners.get(entry.getKey());
           if (spanner != null) {
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/StatementExecutionInterceptor.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/StatementExecutionInterceptor.java
index d8625d2d9f5..159edc3e3d4 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/StatementExecutionInterceptor.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/StatementExecutionInterceptor.java
@@ -36,5 +36,5 @@ enum StatementExecutionStep {
   /** Execution of the statement during an internal transaction retry. */
   RETRY_STATEMENT,
   /** A call to {@link ResultSet#next()} during internal transaction retry. */
-  RETRY_NEXT_ON_RESULT_SET;
+  RETRY_NEXT_ON_RESULT_SET
 }
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/StatementExecutor.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/StatementExecutor.java
index 131533a3374..821ebb1f288 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/StatementExecutor.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/StatementExecutor.java
@@ -144,7 +144,7 @@ org.threeten.bp.Duration asDuration() {
   private static ListeningExecutorService createExecutorService() {
     return MoreExecutors.listeningDecorator(
         new ThreadPoolExecutor(
-            1, 1, 0L, TimeUnit.MILLISECONDS, new LinkedBlockingQueue<Runnable>(), THREAD_FACTORY));
+            1, 1, 0L, TimeUnit.MILLISECONDS, new LinkedBlockingQueue<>(), THREAD_FACTORY));
   }
 
   private ListeningExecutorService executor = createExecutorService();
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/StatementParser.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/StatementParser.java
index 3bfc67908fb..498ea925c95 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/StatementParser.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/StatementParser.java
@@ -50,7 +50,7 @@ enum StatementType {
     DDL,
     QUERY,
     UPDATE,
-    UNKNOWN;
+    UNKNOWN
   }
 
   /** A statement that has been parsed */
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/StatementResult.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/StatementResult.java
index 364ac5307ad..94269d6ac79 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/StatementResult.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/StatementResult.java
@@ -43,7 +43,7 @@ enum ResultType {
      * DDL statements and client side statements that set the state of a connection return no
      * result.
      */
-    NO_RESULT;
+    NO_RESULT
   }
 
   /** The type of client side statement that was executed. */
@@ -74,7 +74,7 @@ enum ClientSideStatementType {
     START_BATCH_DDL,
     START_BATCH_DML,
     RUN_BATCH,
-    ABORT_BATCH;
+    ABORT_BATCH
   }
 
   /**
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/TransactionMode.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/TransactionMode.java
index 1210488689e..0a066fede82 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/TransactionMode.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/TransactionMode.java
@@ -23,7 +23,7 @@ public enum TransactionMode {
 
   private final String statementString;
 
-  private TransactionMode(String statement) {
+  TransactionMode(String statement) {
     this.statementString = statement;
   }
 
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/TransactionRetryListener.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/TransactionRetryListener.java
index dde0fe75a9e..d622d8fde36 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/TransactionRetryListener.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/TransactionRetryListener.java
@@ -38,7 +38,7 @@
 public interface TransactionRetryListener {
   /** The result of a retry. */
   @InternalApi
-  public enum RetryResult {
+  enum RetryResult {
     /** The retry executed successfully and the transaction will continue. */
     RETRY_SUCCESSFUL,
     /** The retry was aborted by Spanner and another retry attempt will be started. */
@@ -58,7 +58,7 @@ public enum RetryResult {
      * An unexpected error occurred during transaction retry, the transaction cannot continue and
      * will throw an exception.
      */
-    RETRY_ERROR;
+    RETRY_ERROR
   }
 
   /**
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/UnitOfWork.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/UnitOfWork.java
index f1b218c751f..1d8de48bf5e 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/UnitOfWork.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/UnitOfWork.java
@@ -37,7 +37,7 @@ interface UnitOfWork {
   /** A unit of work can be either a transaction or a DDL/DML batch. */
   enum Type {
     TRANSACTION,
-    BATCH;
+    BATCH
   }
 
   enum UnitOfWorkState {
@@ -145,7 +145,7 @@ ApiFuture<ResultSet> executeQueryAsync(
 
   /**
    * @return the {@link CommitResponse} of this transaction
-   * @throws {@link SpannerException} if there is no {@link CommitResponse}
+   * @throws SpannerException if there is no {@link CommitResponse}
    */
   CommitResponse getCommitResponse();
 
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/spi/v1/GapicSpannerRpc.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/spi/v1/GapicSpannerRpc.java
index 06629f609be..5d10840ddf3 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/spi/v1/GapicSpannerRpc.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/spi/v1/GapicSpannerRpc.java
@@ -274,7 +274,7 @@ private void awaitTermination() throws InterruptedException {
   private final boolean throttleAdministrativeRequests;
   private static final double ADMINISTRATIVE_REQUESTS_RATE_LIMIT = 1.0D;
   private static final ConcurrentMap<String, RateLimiter> ADMINISTRATIVE_REQUESTS_RATE_LIMITERS =
-      new ConcurrentHashMap<String, RateLimiter>();
+      new ConcurrentHashMap<>();
 
   public static GapicSpannerRpc create(SpannerOptions options) {
     return new GapicSpannerRpc(options);
@@ -968,7 +968,7 @@ public OperationFuture<Database, CreateDatabaseMetadata> createDatabase(
     final CreateDatabaseRequest request = requestBuilder.build();
 
     OperationFutureCallable<CreateDatabaseRequest, Database, CreateDatabaseMetadata> callable =
-        new OperationFutureCallable<CreateDatabaseRequest, Database, CreateDatabaseMetadata>(
+        new OperationFutureCallable<>(
             databaseAdminStub.createDatabaseOperationCallable(),
             request,
             DatabaseAdminGrpc.getCreateDatabaseMethod(),
@@ -1139,7 +1139,7 @@ public OperationFuture<Backup, CreateBackupMetadata> createBackup(
     }
     final CreateBackupRequest request = requestBuilder.build();
     final OperationFutureCallable<CreateBackupRequest, Backup, CreateBackupMetadata> callable =
-        new OperationFutureCallable<CreateBackupRequest, Backup, CreateBackupMetadata>(
+        new OperationFutureCallable<>(
             databaseAdminStub.createBackupOperationCallable(),
             request,
             DatabaseAdminGrpc.getCreateBackupMethod(),
@@ -1198,7 +1198,7 @@ public OperationFuture<Database, RestoreDatabaseMetadata> restoreDatabase(final
 
     final OperationFutureCallable<RestoreDatabaseRequest, Database, RestoreDatabaseMetadata>
         callable =
-            new OperationFutureCallable<RestoreDatabaseRequest, Database, RestoreDatabaseMetadata>(
+            new OperationFutureCallable<>(
                 databaseAdminStub.restoreDatabaseOperationCallable(),
                 requestBuilder.build(),
                 DatabaseAdminGrpc.getRestoreDatabaseMethod(),
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/spi/v1/SpannerRpc.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/spi/v1/SpannerRpc.java
index d4a96508307..fbf9575cf4b 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/spi/v1/SpannerRpc.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/spi/v1/SpannerRpc.java
@@ -110,7 +110,7 @@ public String toString() {
    *
    * @param <T> the type of result
    */
-  public static final class Paginated<T> {
+  final class Paginated<T> {
     private final Iterable<T> results;
     private final String nextPageToken;
 
@@ -354,7 +354,7 @@ TestIamPermissionsResponse testDatabaseAdminIAMPermissions(
   TestIamPermissionsResponse testInstanceAdminIAMPermissions(
       String resource, Iterable<String> permissions);
 
-  public void shutdown();
+  void shutdown();
 
   boolean isClosed();
 }
diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/testing/RemoteSpannerHelper.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/testing/RemoteSpannerHelper.java
index 6d2fe90227c..f6021b2a7d6 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/testing/RemoteSpannerHelper.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/testing/RemoteSpannerHelper.java
@@ -151,7 +151,7 @@ public void cleanUp() {
    * Creates a {@code RemoteSpannerHelper} bound to the given instance ID. All databases created
    * using this will be created in the given instance.
    */
-  public static RemoteSpannerHelper create(InstanceId instanceId) throws Throwable {
+  public static RemoteSpannerHelper create(InstanceId instanceId) {
     SpannerOptions options =
         SpannerOptions.newBuilder()
             .setProjectId(instanceId.getProject())
@@ -166,8 +166,7 @@ public static RemoteSpannerHelper create(InstanceId instanceId) throws Throwable
    * Creates a {@code RemoteSpannerHelper} for the given option and bound to the given instance ID.
    * All databases created using this will be created in the given instance.
    */
-  public static RemoteSpannerHelper create(SpannerOptions options, InstanceId instanceId)
-      throws Throwable {
+  public static RemoteSpannerHelper create(SpannerOptions options, InstanceId instanceId) {
     Spanner client = options.getService();
     return new RemoteSpannerHelper(options, instanceId, client);
   }
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/AsyncResultSetImplStressTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/AsyncResultSetImplStressTest.java
index 6ff398da29f..ae59b480423 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/AsyncResultSetImplStressTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/AsyncResultSetImplStressTest.java
@@ -153,7 +153,7 @@ private ResultSet createResultSetWithErrors(double errorFraction) {
   private List<Row> createExpectedRows() {
     List<Row> rows = new ArrayList<>(resultSetSize);
     for (int i = 0; i < resultSetSize; i++) {
-      rows.add(new Row(Long.valueOf(i + 1), String.format("Row %d", (i + 1))));
+      rows.add(new Row(i + 1L, String.format("Row %d", (i + 1))));
     }
     return rows;
   }
@@ -334,8 +334,7 @@ public void pauseResume() throws Exception {
         new Executor[] {
           MoreExecutors.directExecutor(), createExecService(), createExecService(32)
         }) {
-      final List<AsyncResultSet> resultSets =
-          Collections.synchronizedList(new ArrayList<AsyncResultSet>());
+      final List<AsyncResultSet> resultSets = Collections.synchronizedList(new ArrayList<>());
       for (int bufferSize = 1; bufferSize < resultSetSize * 2; bufferSize *= 2) {
         for (int i = 0; i < TEST_RUNS; i++) {
           final SettableApiFuture<ImmutableList<Row>> future = SettableApiFuture.create();
@@ -396,8 +395,7 @@ public void cancel() throws Exception {
           MoreExecutors.directExecutor(), createExecService(), createExecService(32)
         }) {
       List<ApiFuture<ImmutableList<Row>>> futures = new ArrayList<>();
-      final List<AsyncResultSet> resultSets =
-          Collections.synchronizedList(new ArrayList<AsyncResultSet>());
+      final List<AsyncResultSet> resultSets = Collections.synchronizedList(new ArrayList<>());
       final Set<Integer> cancelledIndexes = new HashSet<>();
       for (int bufferSize = 1; bufferSize < resultSetSize * 2; bufferSize *= 2) {
         for (int i = 0; i < TEST_RUNS; i++) {
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/DatabaseAdminClientTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/DatabaseAdminClientTest.java
index 95641ef3fff..8b0f61c12ac 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/DatabaseAdminClientTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/DatabaseAdminClientTest.java
@@ -694,7 +694,7 @@ public void instanceListDatabaseOperationsWithMetadata() throws Exception {
           op.getMetadata().unpack(OptimizeRestoredDatabaseMetadata.class);
       String progress =
           String.format(
-              "Restored database %s is optimized",
+              "Restored database %s is optimized %d%%",
               metadata.getName(), metadata.getProgress().getProgressPercent());
       assertThat(progress.contains("100%"));
     }
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/DatabaseAdminGaxTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/DatabaseAdminGaxTest.java
index 7e4dfb699c7..aaf851fb0a1 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/DatabaseAdminGaxTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/DatabaseAdminGaxTest.java
@@ -93,7 +93,7 @@ private static Exception createDelayedInternal() {
         500L);
   }
 
-  public static enum ExceptionType {
+  public enum ExceptionType {
     RETRYABLE {
       @Override
       public Exception getException() {
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/DatabaseClientImplTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/DatabaseClientImplTest.java
index 70a0918d336..0e623db2c75 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/DatabaseClientImplTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/DatabaseClientImplTest.java
@@ -1492,7 +1492,7 @@ public void testNestedTransactionsUsingTwoDatabases() throws InterruptedExceptio
                     if (rs.next()) {
                       return add + rs.getLong(0);
                     }
-                    return add + 0L;
+                    return add;
                   }
                 });
     assertThat(res).isEqualTo(2L);
@@ -1824,16 +1824,12 @@ public void testBatchCreateSessionsFailure_shouldNotPropagateToCloseMethod() {
               DatabaseId.of(TEST_PROJECT, TEST_INSTANCE, TEST_DATABASE));
       // This will not cause any failure as getting a session from the pool is guaranteed to be
       // non-blocking, and any exceptions will be delayed until actual query execution.
-      ResultSet rs = client.singleUse().executeQuery(SELECT1);
-      try {
+      try (ResultSet rs = client.singleUse().executeQuery(SELECT1)) {
         while (rs.next()) {
           fail("Missing expected exception");
         }
       } catch (SpannerException e) {
         assertThat(e.getErrorCode()).isEqualTo(ErrorCode.RESOURCE_EXHAUSTED);
-      } finally {
-        // This should not cause any failures.
-        rs.close();
       }
     } finally {
       mockSpanner.setBatchCreateSessionsExecutionTime(SimulatedExecutionTime.none());
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/GrpcResultSetTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/GrpcResultSetTest.java
index 4961229b20f..74eff109379 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/GrpcResultSetTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/GrpcResultSetTest.java
@@ -502,7 +502,7 @@ public void planResult() {
         ResultSetStats.newBuilder().setQueryPlan(QueryPlan.newBuilder().build()).build();
     consumer.onPartialResultSet(
         PartialResultSet.newBuilder()
-            .setMetadata(makeMetadata(Type.struct(new ArrayList<Type.StructField>())))
+            .setMetadata(makeMetadata(Type.struct(new ArrayList<>())))
             .setChunkedValue(false)
             .setStats(stats)
             .build());
@@ -519,7 +519,7 @@ public void statsUnavailable() {
     ResultSetStats stats = ResultSetStats.newBuilder().build();
     consumer.onPartialResultSet(
         PartialResultSet.newBuilder()
-            .setMetadata(makeMetadata(Type.struct(new ArrayList<Type.StructField>())))
+            .setMetadata(makeMetadata(Type.struct(new ArrayList<>())))
             .setChunkedValue(false)
             .setStats(stats)
             .build());
@@ -589,7 +589,7 @@ public void serialization() {
         Value.bytes(null),
         Value.timestamp(Timestamp.ofTimeSecondsAndNanos(1, 2)),
         Value.timestamp(null),
-        Value.date(Date.fromYearMonthDay(2017, 04, 17)),
+        Value.date(Date.fromYearMonthDay(2017, 4, 17)),
         Value.date(null),
         Value.stringArray(ImmutableList.of("one", "two")),
         Value.stringArray(null),
@@ -816,7 +816,7 @@ public void getDoubleArray() {
 
   @Test
   public void getBigDecimalList() {
-    List<BigDecimal> bigDecimalsList = new ArrayList<BigDecimal>();
+    List<BigDecimal> bigDecimalsList = new ArrayList<>();
     bigDecimalsList.add(BigDecimal.valueOf(Double.MIN_VALUE));
     bigDecimalsList.add(BigDecimal.valueOf(Double.MAX_VALUE));
     bigDecimalsList.add(BigDecimal.ZERO);
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/InlineBeginBenchmark.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/InlineBeginBenchmark.java
index 53c80dd8cad..d8c46a2171d 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/InlineBeginBenchmark.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/InlineBeginBenchmark.java
@@ -68,7 +68,7 @@ public class InlineBeginBenchmark {
 
   @State(Scope.Thread)
   public static class BenchmarkState {
-    private final boolean useRealServer = Boolean.valueOf(System.getProperty("useRealServer"));
+    private final boolean useRealServer = Boolean.parseBoolean(System.getProperty("useRealServer"));
     private final String instance = System.getProperty("instance", TEST_INSTANCE);
     private final String database = System.getProperty("database", TEST_DATABASE);
     private StandardBenchmarkMockServer mockServer;
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/InlineBeginTransactionTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/InlineBeginTransactionTest.java
index 85736116d64..fb18f317251 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/InlineBeginTransactionTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/InlineBeginTransactionTest.java
@@ -1002,7 +1002,7 @@ public void testInlinedBeginTxWithParallelQueries() {
                     }
                     return res;
                   });
-      assertThat(updateCount).isEqualTo(1L * numQueries);
+      assertThat(updateCount).isEqualTo((long) numQueries);
       assertThat(countRequests(BeginTransactionRequest.class)).isEqualTo(0);
       assertThat(countTransactionsStarted()).isEqualTo(1);
     }
@@ -1202,7 +1202,7 @@ public ApiFuture<Long> apply(List<Long> input) throws Exception {
                         MoreExecutors.directExecutor());
                   },
                   executor);
-      assertThat(updateCount.get()).isEqualTo(1L * numQueries);
+      assertThat(updateCount.get()).isEqualTo((long) numQueries);
       assertThat(countRequests(BeginTransactionRequest.class)).isEqualTo(0);
       assertThat(countTransactionsStarted()).isEqualTo(1);
     }
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/InstanceAdminClientImplTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/InstanceAdminClientImplTest.java
index bdbbe66fedd..c981da73091 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/InstanceAdminClientImplTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/InstanceAdminClientImplTest.java
@@ -79,12 +79,12 @@ public void listInstanceConfigs() {
     String nextToken = "token";
     when(rpc.listInstanceConfigs(1, null))
         .thenReturn(
-            new Paginated<InstanceConfig>(
+            new Paginated<>(
                 ImmutableList.of(InstanceConfig.newBuilder().setName(CONFIG_NAME).build()),
                 nextToken));
     when(rpc.listInstanceConfigs(1, nextToken))
         .thenReturn(
-            new Paginated<InstanceConfig>(
+            new Paginated<>(
                 ImmutableList.of(InstanceConfig.newBuilder().setName(CONFIG_NAME2).build()), ""));
     List<com.google.cloud.spanner.InstanceConfig> configs =
         Lists.newArrayList(client.listInstanceConfigs(Options.pageSize(1)).iterateAll());
@@ -169,13 +169,9 @@ public void listInstances() {
     String nextToken = "token";
     String filter = "env:dev";
     when(rpc.listInstances(1, null, filter))
-        .thenReturn(
-            new Paginated<com.google.spanner.admin.instance.v1.Instance>(
-                ImmutableList.of(getInstanceProto()), nextToken));
+        .thenReturn(new Paginated<>(ImmutableList.of(getInstanceProto()), nextToken));
     when(rpc.listInstances(1, nextToken, filter))
-        .thenReturn(
-            new Paginated<com.google.spanner.admin.instance.v1.Instance>(
-                ImmutableList.of(getAnotherInstanceProto()), ""));
+        .thenReturn(new Paginated<>(ImmutableList.of(getAnotherInstanceProto()), ""));
     List<Instance> instances =
         Lists.newArrayList(
             client.listInstances(Options.pageSize(1), Options.filter(filter)).iterateAll());
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/InstanceAdminGaxTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/InstanceAdminGaxTest.java
index 34754e72719..8077b4b06e8 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/InstanceAdminGaxTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/InstanceAdminGaxTest.java
@@ -99,7 +99,7 @@ private static Exception createDelayedInternal() {
         1000L);
   }
 
-  public static enum ExceptionType {
+  public enum ExceptionType {
     RETRYABLE {
       @Override
       public Exception getException() {
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/MetricRegistryTestUtils.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/MetricRegistryTestUtils.java
index da3b145271f..546d0c55db4 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/MetricRegistryTestUtils.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/MetricRegistryTestUtils.java
@@ -90,7 +90,7 @@ private FakeDerivedLongGauge(
     public <T> void createTimeSeries(
         List<LabelValue> labelValues, T t, ToLongFunction<T> toLongFunction) {
       if (!this.record.metrics.containsKey(this.name)) {
-        this.record.metrics.put(this.name, new ArrayList<PointWithFunction>());
+        this.record.metrics.put(this.name, new ArrayList<>());
       }
       this.record
           .metrics
@@ -121,7 +121,7 @@ private FakeDerivedLongCumulative(
     public <T> void createTimeSeries(
         List<LabelValue> labelValues, T t, ToLongFunction<T> toLongFunction) {
       if (!this.record.metrics.containsKey(this.name)) {
-        this.record.metrics.put(this.name, new ArrayList<PointWithFunction>());
+        this.record.metrics.put(this.name, new ArrayList<>());
       }
       this.record
           .metrics
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/MockDatabaseAdminServiceImpl.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/MockDatabaseAdminServiceImpl.java
index 25e162039bf..8977002afc4 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/MockDatabaseAdminServiceImpl.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/MockDatabaseAdminServiceImpl.java
@@ -936,11 +936,7 @@ public void addException(Exception exception) {
   }
 
   public void addFilterMatches(String filter, String... names) {
-    Set<String> matches = filterMatches.get(filter);
-    if (matches == null) {
-      matches = new HashSet<>();
-      filterMatches.put(filter, matches);
-    }
+    Set<String> matches = filterMatches.computeIfAbsent(filter, k -> new HashSet<>());
     matches.addAll(Arrays.asList(names));
   }
 
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/MockSpannerServiceImpl.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/MockSpannerServiceImpl.java
index 4850bce5add..1a7e6b2364d 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/MockSpannerServiceImpl.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/MockSpannerServiceImpl.java
@@ -230,7 +230,7 @@ public static class StatementResult {
     private enum StatementResultType {
       RESULT_SET,
       UPDATE_COUNT,
-      EXCEPTION;
+      EXCEPTION
     }
 
     private final StatementResultType type;
@@ -271,11 +271,11 @@ public static StatementResult exception(Statement statement, StatusRuntimeExcept
 
     private static class KeepLastElementDeque<E> extends LinkedList<E> {
       private static <E> KeepLastElementDeque<E> singleton(E item) {
-        return new KeepLastElementDeque<E>(Collections.singleton(item));
+        return new KeepLastElementDeque<>(Collections.singleton(item));
       }
 
       private static <E> KeepLastElementDeque<E> of(E first, E second) {
-        return new KeepLastElementDeque<E>(Arrays.asList(first, second));
+        return new KeepLastElementDeque<>(Arrays.asList(first, second));
       }
 
       private KeepLastElementDeque(Collection<E> coll) {
@@ -588,11 +588,7 @@ private ByteString generateTransactionName(String session) {
   private ByteString generatePartitionToken(String session, ByteString transactionId) {
     ByteString token = ByteString.copyFromUtf8(UUID.randomUUID().toString());
     String key = partitionKey(session, transactionId);
-    List<ByteString> tokens = partitionTokens.get(key);
-    if (tokens == null) {
-      tokens = new ArrayList<>(5);
-      partitionTokens.put(key, tokens);
-    }
+    List<ByteString> tokens = partitionTokens.computeIfAbsent(key, k -> new ArrayList<>(5));
     tokens.add(token);
     return token;
   }
@@ -1147,7 +1143,9 @@ public void executeStreamingSql(
         if (tokens == null || !tokens.contains(request.getPartitionToken())) {
           throw Status.INVALID_ARGUMENT
               .withDescription(
-                  String.format("Partition token %s is not a valid token for this transaction"))
+                  String.format(
+                      "Partition token %s is not a valid token for this transaction",
+                      request.getPartitionToken()))
               .asRuntimeException();
         }
       }
@@ -1467,7 +1465,9 @@ public void streamingRead(
         if (tokens == null || !tokens.contains(request.getPartitionToken())) {
           throw Status.INVALID_ARGUMENT
               .withDescription(
-                  String.format("Partition token %s is not a valid token for this transaction"))
+                  String.format(
+                      "Partition token %s is not a valid token for this transaction",
+                      request.getPartitionToken()))
               .asRuntimeException();
         }
       }
@@ -1591,7 +1591,7 @@ private void returnPartialResultSet(
   private boolean isPartitionedDmlTransaction(ByteString transactionId) {
     return transactionId != null
         && isPartitionedDmlTransaction.get(transactionId) != null
-        && isPartitionedDmlTransaction.get(transactionId).booleanValue();
+        && isPartitionedDmlTransaction.get(transactionId);
   }
 
   private boolean isReadWriteTransaction(ByteString transactionId) {
@@ -1745,7 +1745,7 @@ private void ensureMostRecentTransaction(Session session, ByteString transaction
     if (transactionId != null && transactionId.toStringUtf8() != null && counter != null) {
       int index = transactionId.toStringUtf8().lastIndexOf('/');
       if (index > -1) {
-        long id = Long.valueOf(transactionId.toStringUtf8().substring(index + 1));
+        long id = Long.parseLong(transactionId.toStringUtf8().substring(index + 1));
         if (id != counter.get()) {
           throw Status.FAILED_PRECONDITION
               .withDescription(
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/MutationTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/MutationTest.java
index 12edae44798..16a0f87357e 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/MutationTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/MutationTest.java
@@ -430,7 +430,7 @@ public void javaSerialization() {
                 2.3,
                 ByteArray.fromBase64("abcd"),
                 Timestamp.ofTimeSecondsAndNanos(1, 2),
-                Date.fromYearMonthDay(2017, 04, 17))));
+                Date.fromYearMonthDay(2017, 4, 17))));
     reserializeAndAssert(Mutation.delete("test", KeySet.all()));
     reserializeAndAssert(
         Mutation.delete(
@@ -495,7 +495,7 @@ private Mutation.WriteBuilder appendAllTypes(Mutation.WriteBuilder builder) {
         .set("timestampNull")
         .to((Timestamp) null)
         .set("date")
-        .to(Date.fromYearMonthDay(2017, 04, 17))
+        .to(Date.fromYearMonthDay(2017, 4, 17))
         .set("dateNull")
         .to((Date) null)
         .set("stringArr")
@@ -509,7 +509,7 @@ private Mutation.WriteBuilder appendAllTypes(Mutation.WriteBuilder builder) {
         .set("dateArr")
         .toDateArray(
             ImmutableList.of(
-                Date.fromYearMonthDay(2017, 04, 17), Date.fromYearMonthDay(2017, 04, 18)))
+                Date.fromYearMonthDay(2017, 4, 17), Date.fromYearMonthDay(2017, 4, 18)))
         .set("dateArrNull")
         .toDateArray(null);
   }
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/OptionsTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/OptionsTest.java
index d0f4794ccdd..c57036adac4 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/OptionsTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/OptionsTest.java
@@ -18,7 +18,6 @@
 
 import static com.google.common.truth.Truth.assertThat;
 import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
@@ -111,13 +110,7 @@ public void listOptionsTest() {
 
     assertThat(options.toString())
         .isEqualTo(
-            "pageSize: "
-                + Integer.toString(pageSize)
-                + " pageToken: "
-                + pageToken
-                + " filter: "
-                + filter
-                + " ");
+            "pageSize: " + pageSize + " pageToken: " + pageToken + " filter: " + filter + " ");
 
     assertThat(options.hasPageSize()).isTrue();
     assertThat(options.hasPageToken()).isTrue();
@@ -174,8 +167,7 @@ public void readOptionsTest() {
     String tag = "app=spanner,env=test,action=read";
     Options options = Options.fromReadOptions(Options.limit(limit), Options.tag(tag));
 
-    assertThat(options.toString())
-        .isEqualTo("limit: " + Integer.toString(limit) + " " + "tag: " + tag + " ");
+    assertThat(options.toString()).isEqualTo("limit: " + limit + " " + "tag: " + tag + " ");
     assertThat(options.tag()).isEqualTo(tag);
     assertThat(options.hashCode()).isEqualTo(-1111478426);
   }
@@ -207,7 +199,7 @@ public void queryOptionsTest() {
     String tag = "app=spanner,env=test,action=query";
     Options options = Options.fromQueryOptions(Options.prefetchChunks(chunks), Options.tag(tag));
     assertThat(options.toString())
-        .isEqualTo("prefetchChunks: " + Integer.toString(chunks) + " " + "tag: " + tag + " ");
+        .isEqualTo("prefetchChunks: " + chunks + " " + "tag: " + tag + " ");
     assertThat(options.prefetchChunks()).isEqualTo(chunks);
     assertThat(options.tag()).isEqualTo(tag);
     assertThat(options.hashCode()).isEqualTo(-97431824);
@@ -333,11 +325,11 @@ public void testTransactionOptionsWithPriorityEquality() {
         Options.fromTransactionOptions(Options.priority(RpcPriority.HIGH));
     Options optionsWithHighPriority2 =
         Options.fromTransactionOptions(Options.priority(RpcPriority.HIGH));
-    assertTrue(optionsWithHighPriority1.equals(optionsWithHighPriority2));
+    assertEquals(optionsWithHighPriority1, optionsWithHighPriority2);
 
     Options optionsWithMediumPriority =
         Options.fromTransactionOptions(Options.priority(RpcPriority.MEDIUM));
-    assertFalse(optionsWithHighPriority1.equals(optionsWithMediumPriority));
+    assertNotEquals(optionsWithHighPriority1, optionsWithMediumPriority);
   }
 
   @Test
@@ -357,7 +349,7 @@ public void testTransactionOptionsWithPriorityHashCode() {
   public void testUpdateOptionsEquality() {
     Options option1 = Options.fromUpdateOptions();
     Options option2 = Options.fromUpdateOptions();
-    assertTrue(option1.equals(option2));
+    assertEquals(option1, option2);
   }
 
   @Test
@@ -373,11 +365,11 @@ public void testUpdateOptionsWithPriorityEquality() {
         Options.fromUpdateOptions(Options.priority(RpcPriority.HIGH));
     Options optionsWithHighPriority2 =
         Options.fromUpdateOptions(Options.priority(RpcPriority.HIGH));
-    assertTrue(optionsWithHighPriority1.equals(optionsWithHighPriority2));
+    assertEquals(optionsWithHighPriority1, optionsWithHighPriority2);
 
     Options optionsWithMediumPriority =
         Options.fromUpdateOptions(Options.priority(RpcPriority.MEDIUM));
-    assertFalse(optionsWithHighPriority1.equals(optionsWithMediumPriority));
+    assertNotEquals(optionsWithHighPriority1, optionsWithMediumPriority);
   }
 
   @Test
@@ -397,7 +389,7 @@ public void testUpdateOptionsWithPriorityHashCode() {
   public void testQueryOptionsEquality() {
     Options option1 = Options.fromQueryOptions();
     Options option2 = Options.fromQueryOptions();
-    assertTrue(option1.equals(option2));
+    assertEquals(option1, option2);
   }
 
   @Test
@@ -411,15 +403,15 @@ public void testQueryOptionsHashCode() {
   public void testQueryOptionsWithPriorityEquality() {
     Options optionsWithHighPriority1 = Options.fromQueryOptions(Options.priority(RpcPriority.HIGH));
     Options optionsWithHighPriority2 = Options.fromQueryOptions(Options.priority(RpcPriority.HIGH));
-    assertTrue(optionsWithHighPriority1.equals(optionsWithHighPriority2));
+    assertEquals(optionsWithHighPriority1, optionsWithHighPriority2);
 
     Options optionsWithMediumPriority =
         Options.fromQueryOptions(Options.priority(RpcPriority.MEDIUM));
-    assertFalse(optionsWithHighPriority1.equals(optionsWithMediumPriority));
+    assertNotEquals(optionsWithHighPriority1, optionsWithMediumPriority);
 
     Options optionsWithHighPriorityAndBufferRows =
         Options.fromQueryOptions(Options.priority(RpcPriority.HIGH), Options.bufferRows(10));
-    assertFalse(optionsWithHighPriorityAndBufferRows.equals(optionsWithHighPriority1));
+    assertNotEquals(optionsWithHighPriorityAndBufferRows, optionsWithHighPriority1);
   }
 
   @Test
@@ -442,7 +434,7 @@ public void testQueryOptionsWithPriorityHashCode() {
   public void testReadOptionsEquality() {
     Options option1 = Options.fromReadOptions();
     Options option2 = Options.fromReadOptions();
-    assertTrue(option1.equals(option2));
+    assertEquals(option1, option2);
   }
 
   @Test
@@ -456,15 +448,15 @@ public void testReadOptionsHashCode() {
   public void testReadOptionsWithPriorityEquality() {
     Options optionsWithHighPriority1 = Options.fromReadOptions(Options.priority(RpcPriority.HIGH));
     Options optionsWithHighPriority2 = Options.fromReadOptions(Options.priority(RpcPriority.HIGH));
-    assertTrue(optionsWithHighPriority1.equals(optionsWithHighPriority2));
+    assertEquals(optionsWithHighPriority1, optionsWithHighPriority2);
 
     Options optionsWithMediumPriority =
         Options.fromReadOptions(Options.priority(RpcPriority.MEDIUM));
-    assertFalse(optionsWithHighPriority1.equals(optionsWithMediumPriority));
+    assertNotEquals(optionsWithHighPriority1, optionsWithMediumPriority);
 
     Options optionsWithHighPriorityAndBufferRows =
         Options.fromReadOptions(Options.priority(RpcPriority.HIGH), Options.bufferRows(10));
-    assertFalse(optionsWithHighPriorityAndBufferRows.equals(optionsWithHighPriority1));
+    assertNotEquals(optionsWithHighPriorityAndBufferRows, optionsWithHighPriority1);
   }
 
   @Test
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/PartitionedDmlTransactionTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/PartitionedDmlTransactionTest.java
index 1ca4b853198..a909fbd5706 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/PartitionedDmlTransactionTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/PartitionedDmlTransactionTest.java
@@ -21,7 +21,10 @@
 import static org.junit.Assert.fail;
 import static org.mockito.Matchers.any;
 import static org.mockito.Matchers.anyMap;
-import static org.mockito.Mockito.*;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
 
 import com.google.api.gax.grpc.GrpcStatusCode;
 import com.google.api.gax.rpc.AbortedException;
@@ -33,9 +36,15 @@
 import com.google.common.base.Ticker;
 import com.google.common.collect.ImmutableList;
 import com.google.protobuf.ByteString;
-import com.google.spanner.v1.*;
+import com.google.spanner.v1.BeginTransactionRequest;
+import com.google.spanner.v1.ExecuteSqlRequest;
 import com.google.spanner.v1.ExecuteSqlRequest.QueryMode;
+import com.google.spanner.v1.PartialResultSet;
+import com.google.spanner.v1.RequestOptions;
 import com.google.spanner.v1.RequestOptions.Priority;
+import com.google.spanner.v1.ResultSetStats;
+import com.google.spanner.v1.Transaction;
+import com.google.spanner.v1.TransactionSelector;
 import io.grpc.Status.Code;
 import java.util.Collections;
 import java.util.Iterator;
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/RandomResultSetGenerator.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/RandomResultSetGenerator.java
index 63bc234a417..fc4f999796b 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/RandomResultSetGenerator.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/RandomResultSetGenerator.java
@@ -32,7 +32,7 @@
 import java.util.Random;
 
 public class RandomResultSetGenerator {
-  private static final Type TYPES[] =
+  private static final Type[] TYPES =
       new Type[] {
         Type.newBuilder().setCode(TypeCode.BOOL).build(),
         Type.newBuilder().setCode(TypeCode.INT64).build(),
@@ -94,9 +94,9 @@ public ResultSet generate() {
     ResultSet.Builder builder = ResultSet.newBuilder();
     for (int row = 0; row < rowCount; row++) {
       ListValue.Builder rowBuilder = ListValue.newBuilder();
-      for (int col = 0; col < TYPES.length; col++) {
+      for (Type type : TYPES) {
         Value.Builder valueBuilder = Value.newBuilder();
-        setRandomValue(valueBuilder, TYPES[col]);
+        setRandomValue(valueBuilder, type);
         rowBuilder.addValues(valueBuilder.build());
       }
       builder.addRows(rowBuilder.build());
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/ReadAsyncTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/ReadAsyncTest.java
index ec5524170d9..1d9c37d11bb 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/ReadAsyncTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/ReadAsyncTest.java
@@ -439,7 +439,7 @@ public CallbackResponse cursorReady(AsyncResultSet resultSet) {
         while (!(evenFinished.isDone() && unevenFinished.isDone())) {
           synchronized (lock) {
             if (allValues.peekLast() != null) {
-              if (Integer.valueOf(allValues.peekLast().substring(1)) % 2 == 1) {
+              if (Integer.parseInt(allValues.peekLast().substring(1)) % 2 == 1) {
                 evenRs.resume();
               } else {
                 unevenRs.resume();
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/SessionClientTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/SessionClientTest.java
index 39dfee6a3f1..b4abbacd93f 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/SessionClientTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/SessionClientTest.java
@@ -145,7 +145,7 @@ public void batchCreateAndCloseSessions() {
     final Map<String, String> labels = new HashMap<>();
     labels.put("env", "dev");
     when(spannerOptions.getSessionLabels()).thenReturn(labels);
-    final List<Long> usedChannels = Collections.synchronizedList(new ArrayList<Long>());
+    final List<Long> usedChannels = Collections.synchronizedList(new ArrayList<>());
     when(rpc.batchCreateSessions(
             Mockito.eq(dbName), Mockito.anyInt(), Mockito.eq(labels), Mockito.anyMap()))
         .then(
@@ -208,7 +208,7 @@ public void batchCreateSessionsDistributesMultipleRequestsOverChannels() {
     final String sessionName = dbName + "/sessions/s%d";
     final Map<String, String> labels = Collections.<String, String>emptyMap();
     when(spannerOptions.getSessionLabels()).thenReturn(labels);
-    final Set<Long> usedChannelHintss = Collections.synchronizedSet(new HashSet<Long>());
+    final Set<Long> usedChannelHintss = Collections.synchronizedSet(new HashSet<>());
     when(rpc.batchCreateSessions(
             Mockito.eq(dbName), Mockito.anyInt(), Mockito.eq(labels), Mockito.anyMap()))
         .then(
@@ -263,7 +263,7 @@ public void onSessionCreateFailure(Throwable t, int createFailureForSessionCount
   private enum AddRemoveSetException {
     SET,
     ADD,
-    REMOVE;
+    REMOVE
   }
 
   @SuppressWarnings("unchecked")
@@ -273,7 +273,7 @@ public void batchCreateSessionsWithExceptions() {
       final List<Long> errorOnChannels = new ArrayList<>();
       if (behavior == AddRemoveSetException.REMOVE) {
         for (int c = 0; c < spannerOptions.getNumChannels(); c++) {
-          errorOnChannels.add(Long.valueOf(c));
+          errorOnChannels.add((long) c);
         }
       }
       for (int errorOnChannel = 0;
@@ -283,7 +283,7 @@ public void batchCreateSessionsWithExceptions() {
           case SET:
             errorOnChannels.clear();
           case ADD:
-            errorOnChannels.add(Long.valueOf(errorOnChannel));
+            errorOnChannels.add((long) errorOnChannel);
             break;
           case REMOVE:
             errorOnChannels.remove(Long.valueOf(errorOnChannel));
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/SessionPoolTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/SessionPoolTest.java
index 0cf43e8a38b..e9882050770 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/SessionPoolTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/SessionPoolTest.java
@@ -635,7 +635,7 @@ public Void answer(final InvocationOnMock invocation) {
     clock.currentTimeMillis +=
         clock.currentTimeMillis + (options.getKeepAliveIntervalMinutes() + 5) * 60 * 1000;
     session1 = pool.getSession();
-    session1.writeAtLeastOnceWithOptions(new ArrayList<Mutation>());
+    session1.writeAtLeastOnceWithOptions(new ArrayList<>());
     session1.close();
     runMaintainanceLoop(clock, pool, pool.poolMaintainer.numKeepAliveCycles);
     // The session pool only keeps MinSessions + MaxIdleSessions alive.
@@ -801,7 +801,7 @@ private enum ReadWriteTransactionTestStatementType {
     UPDATE,
     BATCH_UPDATE,
     WRITE,
-    EXCEPTION;
+    EXCEPTION
   }
 
   @SuppressWarnings("unchecked")
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/SpannerOptionsTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/SpannerOptionsTest.java
index 1cf7127b8c7..fbfd468d349 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/SpannerOptionsTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/SpannerOptionsTest.java
@@ -487,7 +487,7 @@ public void testDoNotCacheClosedSpannerInstance() {
     assertThat(service3 == service1, is(false));
     assertThat(service1.isClosed()).isTrue();
     assertThat(service3.isClosed()).isFalse();
-    ;
+
     // Getting another service from the SpannerOptions should return the new cached instance.
     Spanner service4 = options.getService();
     assertThat(service3 == service4, is(true));
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/StructTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/StructTest.java
index 61d2f900cb4..75e49cc642f 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/StructTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/StructTest.java
@@ -226,7 +226,7 @@ public void serialization() {
     Struct arrayStructFieldStruct =
         Struct.newBuilder()
             .set("f1")
-            .toStructArray(simpleStruct.getType(), new ArrayList<Struct>())
+            .toStructArray(simpleStruct.getType(), new ArrayList<>())
             .build();
     reserializeAndAssert(arrayStructFieldStruct);
     arrayStructFieldStruct =
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/TestEnvConfig.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/TestEnvConfig.java
index 8033b20cf81..0d46d664fb2 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/TestEnvConfig.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/TestEnvConfig.java
@@ -21,15 +21,11 @@
 /** Interface for TestEnvConfig. */
 public interface TestEnvConfig {
   /** Returns the options to use to create the Cloud Spanner client for integration tests. */
-  public SpannerOptions spannerOptions();
+  SpannerOptions spannerOptions();
 
-  /**
-   * Custom setup.
-   *
-   * @throws IOException
-   */
-  public void setUp() throws IOException;
+  /** Custom setup. */
+  void setUp() throws IOException;
 
   /** Custom tear down. */
-  public void tearDown();
+  void tearDown();
 }
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/TransactionRunnerImplTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/TransactionRunnerImplTest.java
index 6ca8f88ab90..de3794c26d3 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/TransactionRunnerImplTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/TransactionRunnerImplTest.java
@@ -268,7 +268,7 @@ public void runResourceExhaustedNoRetry() {
 
   @Test
   public void batchDmlAborted() {
-    long updateCount[] = batchDmlException(Code.ABORTED_VALUE);
+    long[] updateCount = batchDmlException(Code.ABORTED_VALUE);
     assertThat(updateCount.length).isEqualTo(2);
     assertThat(updateCount[0]).isEqualTo(1L);
     assertThat(updateCount[1]).isEqualTo(1L);
@@ -365,7 +365,7 @@ private long[] batchDmlException(int status) {
         .thenReturn(ApiFutures.immediateFuture(commitResponse));
     final Statement statement = Statement.of("UPDATE FOO SET BAR=1");
     final AtomicInteger numCalls = new AtomicInteger(0);
-    long updateCount[] =
+    long[] updateCount =
         runner.run(
             transaction1 -> {
               numCalls.incrementAndGet();
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/ValueTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/ValueTest.java
index 72222f72d01..503fd124f74 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/ValueTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/ValueTest.java
@@ -1135,8 +1135,8 @@ public void testEqualsHashCode() {
     tester.addEqualityGroup(
         Value.structArray(structType1, null), Value.structArray(structType1, null));
     tester.addEqualityGroup(
-        Value.structArray(structType1, new ArrayList<Struct>()),
-        Value.structArray(structType1, new ArrayList<Struct>()));
+        Value.structArray(structType1, new ArrayList<>()),
+        Value.structArray(structType1, new ArrayList<>()));
 
     tester.testEquals();
   }
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/AbstractConnectionImplTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/AbstractConnectionImplTest.java
index cb1fba694c2..9d17398207d 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/AbstractConnectionImplTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/AbstractConnectionImplTest.java
@@ -37,6 +37,7 @@
 import java.io.IOException;
 import java.io.OutputStreamWriter;
 import java.io.PrintWriter;
+import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
@@ -59,7 +60,7 @@ public abstract class AbstractConnectionImplTest {
   public static final String DDL =
       "CREATE TABLE foo (id INT64 NOT NULL, name STRING(100)) PRIMARY KEY (id)";
 
-  static interface ConnectionConsumer {
+  interface ConnectionConsumer {
     void accept(Connection connection);
   }
 
@@ -113,7 +114,7 @@ void log(String statement) {
 
   @BeforeClass
   public static void openLog() {
-    doLog = Boolean.valueOf(System.getProperty(DO_LOG_PROPERTY, "false"));
+    doLog = Boolean.parseBoolean(System.getProperty(DO_LOG_PROPERTY, "false"));
     if (doLog) {
       openLog(true);
     } else {
@@ -125,7 +126,9 @@ private static void openLog(boolean append) {
     try {
       writer =
           new PrintWriter(
-              new OutputStreamWriter(new FileOutputStream(LOG_FILE, append), "UTF8"), true);
+              new OutputStreamWriter(
+                  new FileOutputStream(LOG_FILE, append), StandardCharsets.UTF_8),
+              true);
     } catch (IOException e) {
       throw new RuntimeException(e);
     }
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/AbstractSqlScriptVerifier.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/AbstractSqlScriptVerifier.java
index e0452013fa9..45abf7997f4 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/AbstractSqlScriptVerifier.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/AbstractSqlScriptVerifier.java
@@ -150,8 +150,8 @@ protected abstract static class GenericResultSet {
     protected abstract Object getFirstValue() throws Exception;
   }
 
-  public static interface GenericConnectionProvider {
-    public GenericConnection getConnection();
+  public interface GenericConnectionProvider {
+    GenericConnection getConnection();
   }
 
   /** Reads SQL statements from a file. Any copyright header in the file will be stripped away. */
@@ -163,7 +163,6 @@ public static List<String> readStatementsFromFile(String filename, Class<?> reso
           String line = scanner.nextLine();
           builder.append(line).append("\n");
         }
-        scanner.close();
       }
       String script = builder.toString().replaceAll(StatementParserTest.COPYRIGHT_PATTERN, "");
       String[] array = script.split(";");
@@ -213,7 +212,6 @@ public AbstractSqlScriptVerifier(GenericConnectionProvider provider) {
    *     semicolon (;)
    * @param resourceClass The class that should be used to locate the resource specified by the file
    *     name
-   * @throws Exception
    */
   public void verifyStatementsInFile(String filename, Class<?> resourceClass) throws Exception {
     verifyStatementsInFile(connectionProvider.getConnection(), filename, resourceClass);
@@ -313,7 +311,7 @@ private void verifyStatement(GenericConnection connection, String statement) thr
             } else {
               String value = verifyMatcher.group("value");
               if (value != null) {
-                String parts[] = column.split(",", 2);
+                String[] parts = column.split(",", 2);
                 column = parts[0].trim();
                 value = parts[1].trim();
                 column = column.substring(1, column.length() - 1);
@@ -326,7 +324,7 @@ private void verifyStatement(GenericConnection connection, String statement) thr
             }
             break;
           case UPDATE_COUNT:
-            long expectedUpdateCount = Long.valueOf(verifyMatcher.group("count").trim());
+            long expectedUpdateCount = Long.parseLong(verifyMatcher.group("count").trim());
             assertThat(statement, result.getUpdateCount(), is(equalTo(expectedUpdateCount)));
             break;
         }
@@ -383,8 +381,8 @@ private Object parseValue(String valueString) {
     if (ARRAY_INT64_PATTERN.matcher(valueString).matches()) {
       String[] stringArray = valueString.substring(1, valueString.length() - 1).split(",");
       List<Long> res = new ArrayList<>();
-      for (int i = 0; i < stringArray.length; i++) {
-        res.add(Long.valueOf(stringArray[i]));
+      for (String string : stringArray) {
+        res.add(Long.valueOf(string));
       }
       return res;
     }
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/ClientSideStatementsTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/ClientSideStatementsTest.java
index 11be434f6e0..b36da9c7ac6 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/ClientSideStatementsTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/ClientSideStatementsTest.java
@@ -25,6 +25,7 @@
 import java.io.IOException;
 import java.io.OutputStreamWriter;
 import java.io.PrintWriter;
+import java.nio.charset.StandardCharsets;
 import java.util.List;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -94,7 +95,9 @@ private static void openLog() {
     try {
       writer =
           new PrintWriter(
-              new OutputStreamWriter(new FileOutputStream(SCRIPT_FILE, false), "UTF8"), true);
+              new OutputStreamWriter(
+                  new FileOutputStream(SCRIPT_FILE, false), StandardCharsets.UTF_8),
+              true);
     } catch (IOException e) {
       throw new RuntimeException(e);
     }
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/ConnectionImplTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/ConnectionImplTest.java
index f2c6213226a..41782eecb40 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/ConnectionImplTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/ConnectionImplTest.java
@@ -337,38 +337,36 @@ public Timestamp answer(InvocationOnMock invocation) {
             new Answer<TransactionRunner>() {
               @Override
               public TransactionRunner answer(InvocationOnMock invocation) {
-                TransactionRunner runner =
-                    new TransactionRunner() {
-                      private CommitResponse commitResponse;
-
-                      @Override
-                      public <T> T run(TransactionCallable<T> callable) {
-                        commitResponse = new CommitResponse(Timestamp.ofTimeSecondsAndNanos(1, 1));
-                        TransactionContext transaction = mock(TransactionContext.class);
-                        when(transaction.executeUpdate(Statement.of(UPDATE))).thenReturn(1L);
-                        try {
-                          return callable.run(transaction);
-                        } catch (Exception e) {
-                          throw SpannerExceptionFactory.newSpannerException(e);
-                        }
-                      }
-
-                      @Override
-                      public Timestamp getCommitTimestamp() {
-                        return commitResponse == null ? null : commitResponse.getCommitTimestamp();
-                      }
-
-                      @Override
-                      public CommitResponse getCommitResponse() {
-                        return commitResponse;
-                      }
-
-                      @Override
-                      public TransactionRunner allowNestedTransaction() {
-                        return this;
-                      }
-                    };
-                return runner;
+                return new TransactionRunner() {
+                  private CommitResponse commitResponse;
+
+                  @Override
+                  public <T> T run(TransactionCallable<T> callable) {
+                    commitResponse = new CommitResponse(Timestamp.ofTimeSecondsAndNanos(1, 1));
+                    TransactionContext transaction = mock(TransactionContext.class);
+                    when(transaction.executeUpdate(Statement.of(UPDATE))).thenReturn(1L);
+                    try {
+                      return callable.run(transaction);
+                    } catch (Exception e) {
+                      throw SpannerExceptionFactory.newSpannerException(e);
+                    }
+                  }
+
+                  @Override
+                  public Timestamp getCommitTimestamp() {
+                    return commitResponse == null ? null : commitResponse.getCommitTimestamp();
+                  }
+
+                  @Override
+                  public CommitResponse getCommitResponse() {
+                    return commitResponse;
+                  }
+
+                  @Override
+                  public TransactionRunner allowNestedTransaction() {
+                    return this;
+                  }
+                };
               }
             });
     return new ConnectionImpl(options, spannerPool, ddlClient, dbClient);
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/ConnectionStatementWithOneParameterTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/ConnectionStatementWithOneParameterTest.java
index 56c5c689b0d..62c4cb2974c 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/ConnectionStatementWithOneParameterTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/ConnectionStatementWithOneParameterTest.java
@@ -56,9 +56,7 @@ public void testExecuteSetReadOnly() {
     when(executor.getConnection()).thenReturn(connection);
     when(executor.statementSetReadOnly(any(Boolean.class))).thenCallRealMethod();
     for (Boolean mode : new Boolean[] {Boolean.FALSE, Boolean.TRUE}) {
-      subject
-          .getClientSideStatement()
-          .execute(executor, String.format("set readonly = %s", Boolean.toString(mode)));
+      subject.getClientSideStatement().execute(executor, String.format("set readonly = %s", mode));
       verify(connection, times(1)).setReadOnly(mode);
     }
   }
@@ -102,9 +100,8 @@ public void testExecuteSetStatementTimeout() {
         verify(connection, times(1)).setStatementTimeout(val, unit);
       }
     }
-    ParsedStatement subject =
-        parser.parse(Statement.of(String.format("set statement_timeout=null")));
-    subject.getClientSideStatement().execute(executor, String.format("set statement_timeout=null"));
+    ParsedStatement subject = parser.parse(Statement.of("set statement_timeout=null"));
+    subject.getClientSideStatement().execute(executor, "set statement_timeout=null");
     verify(connection, times(1)).clearStatementTimeout();
   }
 
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/RandomResultSetGenerator.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/RandomResultSetGenerator.java
index 9bb69322193..1560aea76d2 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/RandomResultSetGenerator.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/RandomResultSetGenerator.java
@@ -37,7 +37,7 @@
  * of Cloud Spanner filled with random data.
  */
 public class RandomResultSetGenerator {
-  private static final Type TYPES[] =
+  private static final Type[] TYPES =
       new Type[] {
         Type.newBuilder().setCode(TypeCode.BOOL).build(),
         Type.newBuilder().setCode(TypeCode.INT64).build(),
@@ -104,9 +104,9 @@ public ResultSet generate() {
     ResultSet.Builder builder = ResultSet.newBuilder();
     for (int row = 0; row < rowCount; row++) {
       ListValue.Builder rowBuilder = ListValue.newBuilder();
-      for (int col = 0; col < TYPES.length; col++) {
+      for (Type type : TYPES) {
         Value.Builder valueBuilder = Value.newBuilder();
-        setRandomValue(valueBuilder, TYPES[col]);
+        setRandomValue(valueBuilder, type);
         rowBuilder.addValues(valueBuilder.build());
       }
       builder.addRows(rowBuilder.build());
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/ReadWriteTransactionTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/ReadWriteTransactionTest.java
index d5fee4d6ff4..e1b124a2368 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/ReadWriteTransactionTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/ReadWriteTransactionTest.java
@@ -71,7 +71,7 @@ public class ReadWriteTransactionTest {
   private enum CommitBehavior {
     SUCCEED,
     FAIL,
-    ABORT;
+    ABORT
   }
 
   private static class SimpleTransactionManager implements TransactionManager {
@@ -417,7 +417,7 @@ public void testIsReadOnly() {
 
   private enum RetryResults {
     SAME,
-    DIFFERENT;
+    DIFFERENT
   }
 
   @Test
@@ -508,7 +508,7 @@ public void testChecksumResultSet() {
             Arrays.asList(
                 Struct.newBuilder()
                     .set("ID")
-                    .to(1l)
+                    .to(1L)
                     .set("NAME")
                     .to("TEST 1")
                     .set("AMOUNT")
@@ -516,7 +516,7 @@ public void testChecksumResultSet() {
                     .build(),
                 Struct.newBuilder()
                     .set("ID")
-                    .to(2l)
+                    .to(2L)
                     .set("NAME")
                     .to("TEST 2")
                     .set("AMOUNT")
@@ -533,7 +533,7 @@ public void testChecksumResultSet() {
             Arrays.asList(
                 Struct.newBuilder()
                     .set("ID")
-                    .to(1l)
+                    .to(1L)
                     .set("NAME")
                     .to("TEST 1")
                     .set("AMOUNT")
@@ -541,7 +541,7 @@ public void testChecksumResultSet() {
                     .build(),
                 Struct.newBuilder()
                     .set("ID")
-                    .to(2l)
+                    .to(2L)
                     .set("NAME")
                     .to("TEST 2")
                     .set("AMOUNT")
@@ -559,7 +559,7 @@ public void testChecksumResultSet() {
             Arrays.asList(
                 Struct.newBuilder()
                     .set("ID")
-                    .to(2l)
+                    .to(2L)
                     .set("NAME")
                     .to("TEST 2")
                     .set("AMOUNT")
@@ -567,7 +567,7 @@ public void testChecksumResultSet() {
                     .build(),
                 Struct.newBuilder()
                     .set("ID")
-                    .to(1l)
+                    .to(1L)
                     .set("NAME")
                     .to("TEST 1")
                     .set("AMOUNT")
@@ -586,7 +586,7 @@ public void testChecksumResultSet() {
             Arrays.asList(
                 Struct.newBuilder()
                     .set("ID")
-                    .to(1l)
+                    .to(1L)
                     .set("NAME")
                     .to("TEST 1")
                     .set("AMOUNT")
@@ -594,7 +594,7 @@ public void testChecksumResultSet() {
                     .build(),
                 Struct.newBuilder()
                     .set("ID")
-                    .to(2l)
+                    .to(2L)
                     .set("NAME")
                     .to("TEST 2")
                     .set("AMOUNT")
@@ -602,7 +602,7 @@ public void testChecksumResultSet() {
                     .build(),
                 Struct.newBuilder()
                     .set("ID")
-                    .to(3l)
+                    .to(3L)
                     .set("NAME")
                     .to("TEST 3")
                     .set("AMOUNT")
@@ -646,13 +646,13 @@ public void testChecksumResultSetWithArray() {
             Arrays.asList(
                 Struct.newBuilder()
                     .set("ID")
-                    .to(1l)
+                    .to(1L)
                     .set("PRICES")
                     .toInt64Array(new long[] {1L, 2L})
                     .build(),
                 Struct.newBuilder()
                     .set("ID")
-                    .to(2l)
+                    .to(2L)
                     .set("PRICES")
                     .toInt64Array(new long[] {3L, 4L})
                     .build()));
@@ -666,13 +666,13 @@ public void testChecksumResultSetWithArray() {
             Arrays.asList(
                 Struct.newBuilder()
                     .set("ID")
-                    .to(1l)
+                    .to(1L)
                     .set("PRICES")
                     .toInt64Array(new long[] {1L, 2L})
                     .build(),
                 Struct.newBuilder()
                     .set("ID")
-                    .to(2l)
+                    .to(2L)
                     .set("PRICES")
                     .toInt64Array(new long[] {3L, 5L})
                     .build()));
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/SingleUseTransactionTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/SingleUseTransactionTest.java
index 0c5a5881a76..c994d075bd3 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/SingleUseTransactionTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/SingleUseTransactionTest.java
@@ -83,7 +83,7 @@ public class SingleUseTransactionTest {
   private enum CommitBehavior {
     SUCCEED,
     FAIL,
-    ABORT;
+    ABORT
   }
 
   /** Creates a {@link StatementTimeout} that will never timeout. */
@@ -395,52 +395,49 @@ public Long answer(InvocationOnMock invocation) throws Throwable {
             new Answer<TransactionRunner>() {
               @Override
               public TransactionRunner answer(InvocationOnMock invocation) {
-                TransactionRunner runner =
-                    new TransactionRunner() {
-                      private CommitResponse commitResponse;
-
-                      @Override
-                      public <T> T run(TransactionCallable<T> callable) {
-                        if (commitBehavior == CommitBehavior.SUCCEED) {
-                          T res;
-                          try {
-                            res = callable.run(txContext);
-                          } catch (Exception e) {
-                            throw SpannerExceptionFactory.newSpannerException(e);
-                          }
-                          commitResponse =
-                              new CommitResponse(Timestamp.ofTimeSecondsAndNanos(1, 1));
-                          return res;
-                        } else if (commitBehavior == CommitBehavior.FAIL) {
-                          throw SpannerExceptionFactory.newSpannerException(
-                              ErrorCode.UNKNOWN, "commit failed");
-                        } else {
-                          throw SpannerExceptionFactory.newSpannerException(
-                              ErrorCode.ABORTED, "commit aborted");
-                        }
+                return new TransactionRunner() {
+                  private CommitResponse commitResponse;
+
+                  @Override
+                  public <T> T run(TransactionCallable<T> callable) {
+                    if (commitBehavior == CommitBehavior.SUCCEED) {
+                      T res;
+                      try {
+                        res = callable.run(txContext);
+                      } catch (Exception e) {
+                        throw SpannerExceptionFactory.newSpannerException(e);
                       }
-
-                      @Override
-                      public Timestamp getCommitTimestamp() {
-                        if (commitResponse == null) {
-                          throw new IllegalStateException("no commit timestamp");
-                        }
-                        return commitResponse.getCommitTimestamp();
-                      }
-
-                      public CommitResponse getCommitResponse() {
-                        if (commitResponse == null) {
-                          throw new IllegalStateException("no commit response");
-                        }
-                        return commitResponse;
-                      }
-
-                      @Override
-                      public TransactionRunner allowNestedTransaction() {
-                        return this;
-                      }
-                    };
-                return runner;
+                      commitResponse = new CommitResponse(Timestamp.ofTimeSecondsAndNanos(1, 1));
+                      return res;
+                    } else if (commitBehavior == CommitBehavior.FAIL) {
+                      throw SpannerExceptionFactory.newSpannerException(
+                          ErrorCode.UNKNOWN, "commit failed");
+                    } else {
+                      throw SpannerExceptionFactory.newSpannerException(
+                          ErrorCode.ABORTED, "commit aborted");
+                    }
+                  }
+
+                  @Override
+                  public Timestamp getCommitTimestamp() {
+                    if (commitResponse == null) {
+                      throw new IllegalStateException("no commit timestamp");
+                    }
+                    return commitResponse.getCommitTimestamp();
+                  }
+
+                  public CommitResponse getCommitResponse() {
+                    if (commitResponse == null) {
+                      throw new IllegalStateException("no commit response");
+                    }
+                    return commitResponse;
+                  }
+
+                  @Override
+                  public TransactionRunner allowNestedTransaction() {
+                    return this;
+                  }
+                };
               }
             });
 
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/SpannerPoolTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/SpannerPoolTest.java
index 4e1238077e2..126bab1f239 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/SpannerPoolTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/connection/SpannerPoolTest.java
@@ -17,8 +17,8 @@
 package com.google.cloud.spanner.connection;
 
 import static com.google.common.truth.Truth.assertThat;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
 import static org.junit.Assert.fail;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.never;
@@ -455,9 +455,9 @@ public void testSpannerPoolKeyEquality() {
     SpannerPoolKey key2 = SpannerPoolKey.of(options2);
     SpannerPoolKey key3 = SpannerPoolKey.of(options3);
 
-    assertFalse(key1.equals(key2));
-    assertTrue(key2.equals(key3));
-    assertFalse(key1.equals(key3));
-    assertFalse(key1.equals(new Object()));
+    assertNotEquals(key1, key2);
+    assertEquals(key2, key3);
+    assertNotEquals(key1, key3);
+    assertNotEquals(key1, new Object());
   }
 }
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITAsyncExamplesTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITAsyncExamplesTest.java
index e08d59ab296..ba6f55497a3 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITAsyncExamplesTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITAsyncExamplesTest.java
@@ -462,7 +462,7 @@ public CallbackResponse cursorReady(AsyncResultSet resultSet) {
         while (!(evenFinished.isDone() && unevenFinished.isDone())) {
           synchronized (lock) {
             if (allValues.peekLast() != null) {
-              if (Integer.valueOf(allValues.peekLast().substring(1)) % 2 == 1) {
+              if (Integer.parseInt(allValues.peekLast().substring(1)) % 2 == 1) {
                 evenRs.resume();
               } else {
                 unevenRs.resume();
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITCommitTimestampTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITCommitTimestampTest.java
index 187f1e9f129..1fac4595f7a 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITCommitTimestampTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITCommitTimestampTest.java
@@ -312,7 +312,6 @@ public void interleavedTableHierarchy1() {
             "CREATE TABLE T3 (ts TIMESTAMP OPTIONS (allow_commit_timestamp = true)) "
                 + "PRIMARY KEY (ts), INTERLEAVE IN PARENT T2");
     DatabaseClient client = testHelper.getDatabaseClient(db);
-    db.getId().getDatabase();
 
     // error_catalog error CommitTimestampOptionNotEnabled
     try {
@@ -340,7 +339,6 @@ public void interleavedTableHierarchy2() {
             "CREATE TABLE T3 (ts TIMESTAMP OPTIONS (allow_commit_timestamp = true)) "
                 + "PRIMARY KEY (ts), INTERLEAVE IN PARENT T2");
     DatabaseClient client = testHelper.getDatabaseClient(db);
-    db.getId().getDatabase();
 
     // error_catalog error CommitTimestampOptionNotEnabled
     try {
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITDirectPathFallback.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITDirectPathFallback.java
index 746214e7f2f..80234cbc1a0 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITDirectPathFallback.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITDirectPathFallback.java
@@ -110,7 +110,7 @@ public ITDirectPathFallback() {
   }
 
   @Before
-  public void setup() throws IOException, Throwable {
+  public void setup() {
     assume()
         .withMessage("DirectPath integration tests can only run against DirectPathEnv")
         .that(Boolean.getBoolean(ATTEMPT_DIRECT_PATH))
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITQueryTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITQueryTest.java
index 02b2dac2d8e..b66128a9ea9 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITQueryTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITQueryTest.java
@@ -773,7 +773,7 @@ public void bindEmptyArrayOfStruct() {
 
   @Test
   public void bindStructWithNullStructField() {
-    Type emptyStructType = Type.struct(new ArrayList<StructField>());
+    Type emptyStructType = Type.struct(new ArrayList<>());
     Struct p = Struct.newBuilder().set("f1").to(emptyStructType, null).build();
 
     Struct row =
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITTransactionTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITTransactionTest.java
index dd5746fd429..1b401dcedff 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITTransactionTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITTransactionTest.java
@@ -97,7 +97,7 @@ private static String uniqueKey() {
     return "k" + seq++;
   }
 
-  private static interface ReadStrategy {
+  private interface ReadStrategy {
     Struct read(ReadContext ctx, String key);
   }
 
@@ -157,7 +157,7 @@ public void run() {
                 .singleUse(TimestampBound.strong())
                 .readRow("T", Key.of(key), Arrays.asList("V"))
                 .getLong(0))
-        .isEqualTo(Long.valueOf(numThreads));
+        .isEqualTo((long) numThreads);
   }
 
   @Test
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITVPCNegativeTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITVPCNegativeTest.java
index 63c1560e2f4..230a252bb9d 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITVPCNegativeTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/it/ITVPCNegativeTest.java
@@ -18,7 +18,7 @@
 
 import static com.google.common.truth.Truth.assertThat;
 import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.fail;
 import static org.junit.Assume.assumeTrue;
 
@@ -47,7 +47,6 @@
 import com.google.longrunning.OperationsClient;
 import com.google.longrunning.OperationsSettings;
 import java.io.FileInputStream;
-import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -83,10 +82,10 @@ public static void setUpClass() {
     assumeTrue(
         "To run tests, GOOGLE_CLOUD_TESTS_IN_VPCSC environment variable needs to be set to True",
         IN_VPCSC_TEST != null && IN_VPCSC_TEST.equalsIgnoreCase("true"));
-    assertTrue(
+    assertFalse(
         "GOOGLE_CLOUD_TESTS_VPCSC_OUTSIDE_PERIMETER_PROJECT environment variable needs "
             + "to be set to a GCP project that is outside the VPC perimeter",
-        OUTSIDE_VPC_PROJECT != null && OUTSIDE_VPC_PROJECT != "");
+        Strings.isNullOrEmpty(OUTSIDE_VPC_PROJECT));
     assumeTrue(Strings.isNullOrEmpty(System.getenv("SPANNER_EMULATOR_HOST")));
   }
 
@@ -343,7 +342,7 @@ public void deniedGetBackupOperation() {
   }
 
   @Test
-  public void deniedListBackupOperations() throws FileNotFoundException, IOException {
+  public void deniedListBackupOperations() throws IOException {
     try (OperationsClient client =
         OperationsClient.create(
             OperationsSettings.newBuilder()
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/spi/v1/GapicSpannerRpcTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/spi/v1/GapicSpannerRpcTest.java
index 2e46cc66735..30737dcf719 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/spi/v1/GapicSpannerRpcTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/spi/v1/GapicSpannerRpcTest.java
@@ -195,7 +195,7 @@ public <ReqT, RespT> ServerCall.Listener<ReqT> interceptCall(
                 })
             .build()
             .start();
-    optionsMap.put(Option.CHANNEL_HINT, Long.valueOf(1L));
+    optionsMap.put(Option.CHANNEL_HINT, 1L);
   }
 
   @After