[SPARK-9534] [BUILD] Enable javac lint for scalac parity; fix a lot of build warnings, 1.5.0 edition

Enable most javac lint warnings; fix a lot of build warnings. In a few cases, touch up surrounding code in the process.

I'll explain several of the changes inline in comments.

Author: Sean Owen <sowen@cloudera.com>

Closes #7862 from srowen/SPARK-9534 and squashes the following commits:

ea51618 [Sean Owen] Enable most javac lint warnings; fix a lot of build warnings. In a few cases, touch up surrounding code in the process.

10 files changed, 73 insertions, 31 deletions

diff --git a/network/common/src/main/java/org/apache/spark/network/protocol/ChunkFetchFailure.java b/network/common/src/main/java/org/apache/spark/network/protocol/ChunkFetchFailure.java
index f76bb49e87..f0363830b6 100644
--- a/network/common/src/main/java/org/apache/spark/network/protocol/ChunkFetchFailure.java
+++ b/network/common/src/main/java/org/apache/spark/network/protocol/ChunkFetchFailure.java
@@ -53,6 +53,11 @@ public final class ChunkFetchFailure implements ResponseMessage {
   }
 
   @Override
+  public int hashCode() {
+    return Objects.hashCode(streamChunkId, errorString);
+  }
+
+  @Override
   public boolean equals(Object other) {
     if (other instanceof ChunkFetchFailure) {
       ChunkFetchFailure o = (ChunkFetchFailure) other;
diff --git a/network/common/src/main/java/org/apache/spark/network/protocol/ChunkFetchRequest.java b/network/common/src/main/java/org/apache/spark/network/protocol/ChunkFetchRequest.java
index 980947cf13..5a173af54f 100644
--- a/network/common/src/main/java/org/apache/spark/network/protocol/ChunkFetchRequest.java
+++ b/network/common/src/main/java/org/apache/spark/network/protocol/ChunkFetchRequest.java
@@ -49,6 +49,11 @@ public final class ChunkFetchRequest implements RequestMessage {
   }
 
   @Override
+  public int hashCode() {
+    return streamChunkId.hashCode();
+  }
+
+  @Override
   public boolean equals(Object other) {
     if (other instanceof ChunkFetchRequest) {
       ChunkFetchRequest o = (ChunkFetchRequest) other;
diff --git a/network/common/src/main/java/org/apache/spark/network/protocol/ChunkFetchSuccess.java b/network/common/src/main/java/org/apache/spark/network/protocol/ChunkFetchSuccess.java
index ff4936470c..c962fb7ecf 100644
--- a/network/common/src/main/java/org/apache/spark/network/protocol/ChunkFetchSuccess.java
+++ b/network/common/src/main/java/org/apache/spark/network/protocol/ChunkFetchSuccess.java
@@ -62,6 +62,11 @@ public final class ChunkFetchSuccess implements ResponseMessage {
   }
 
   @Override
+  public int hashCode() {
+    return Objects.hashCode(streamChunkId, buffer);
+  }
+
+  @Override
   public boolean equals(Object other) {
     if (other instanceof ChunkFetchSuccess) {
       ChunkFetchSuccess o = (ChunkFetchSuccess) other;
diff --git a/network/common/src/main/java/org/apache/spark/network/protocol/RpcFailure.java b/network/common/src/main/java/org/apache/spark/network/protocol/RpcFailure.java
index 6b991375fc..2dfc7876ba 100644
--- a/network/common/src/main/java/org/apache/spark/network/protocol/RpcFailure.java
+++ b/network/common/src/main/java/org/apache/spark/network/protocol/RpcFailure.java
@@ -51,6 +51,11 @@ public final class RpcFailure implements ResponseMessage {
   }
 
   @Override
+  public int hashCode() {
+    return Objects.hashCode(requestId, errorString);
+  }
+
+  @Override
   public boolean equals(Object other) {
     if (other instanceof RpcFailure) {
       RpcFailure o = (RpcFailure) other;
diff --git a/network/common/src/main/java/org/apache/spark/network/protocol/RpcRequest.java b/network/common/src/main/java/org/apache/spark/network/protocol/RpcRequest.java
index cdee0b0e03..745039db74 100644
--- a/network/common/src/main/java/org/apache/spark/network/protocol/RpcRequest.java
+++ b/network/common/src/main/java/org/apache/spark/network/protocol/RpcRequest.java
@@ -60,6 +60,11 @@ public final class RpcRequest implements RequestMessage {
   }
 
   @Override
+  public int hashCode() {
+    return Objects.hashCode(requestId, Arrays.hashCode(message));
+  }
+
+  @Override
   public boolean equals(Object other) {
     if (other instanceof RpcRequest) {
       RpcRequest o = (RpcRequest) other;
diff --git a/network/common/src/main/java/org/apache/spark/network/protocol/RpcResponse.java b/network/common/src/main/java/org/apache/spark/network/protocol/RpcResponse.java
index 0a62e09a81..1671cd444f 100644
--- a/network/common/src/main/java/org/apache/spark/network/protocol/RpcResponse.java
+++ b/network/common/src/main/java/org/apache/spark/network/protocol/RpcResponse.java
@@ -51,6 +51,11 @@ public final class RpcResponse implements ResponseMessage {
   }
 
   @Override
+  public int hashCode() {
+    return Objects.hashCode(requestId, Arrays.hashCode(response));
+  }
+
+  @Override
   public boolean equals(Object other) {
     if (other instanceof RpcResponse) {
       RpcResponse o = (RpcResponse) other;
diff --git a/network/common/src/test/java/org/apache/spark/network/TestManagedBuffer.java b/network/common/src/test/java/org/apache/spark/network/TestManagedBuffer.java
index 38113a918f..83c90f9eff 100644
--- a/network/common/src/test/java/org/apache/spark/network/TestManagedBuffer.java
+++ b/network/common/src/test/java/org/apache/spark/network/TestManagedBuffer.java
@@ -81,6 +81,11 @@ public class TestManagedBuffer extends ManagedBuffer {
   }
 
   @Override
+  public int hashCode() {
+    return underlying.hashCode();
+  }
+
+  @Override
   public boolean equals(Object other) {
     if (other instanceof ManagedBuffer) {
       try {
diff --git a/network/common/src/test/java/org/apache/spark/network/sasl/SparkSaslSuite.java b/network/common/src/test/java/org/apache/spark/network/sasl/SparkSaslSuite.java
index be6632bb8c..8104004847 100644
--- a/network/common/src/test/java/org/apache/spark/network/sasl/SparkSaslSuite.java
+++ b/network/common/src/test/java/org/apache/spark/network/sasl/SparkSaslSuite.java
@@ -17,11 +17,11 @@
 
 package org.apache.spark.network.sasl;
 
-import static com.google.common.base.Charsets.UTF_8;
 import static org.junit.Assert.*;
 import static org.mockito.Mockito.*;
 
 import java.io.File;
+import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Random;
@@ -138,8 +138,8 @@ public class SparkSaslSuite {
         public Void answer(InvocationOnMock invocation) {
           byte[] message = (byte[]) invocation.getArguments()[1];
           RpcResponseCallback cb = (RpcResponseCallback) invocation.getArguments()[2];
-          assertEquals("Ping", new String(message, UTF_8));
-          cb.onSuccess("Pong".getBytes(UTF_8));
+          assertEquals("Ping", new String(message, StandardCharsets.UTF_8));
+          cb.onSuccess("Pong".getBytes(StandardCharsets.UTF_8));
           return null;
         }
       })
@@ -148,8 +148,9 @@ public class SparkSaslSuite {
 
     SaslTestCtx ctx = new SaslTestCtx(rpcHandler, encrypt, false);
     try {
-      byte[] response = ctx.client.sendRpcSync("Ping".getBytes(UTF_8), TimeUnit.SECONDS.toMillis(10));
-      assertEquals("Pong", new String(response, UTF_8));
+      byte[] response = ctx.client.sendRpcSync("Ping".getBytes(StandardCharsets.UTF_8),
+                                               TimeUnit.SECONDS.toMillis(10));
+      assertEquals("Pong", new String(response, StandardCharsets.UTF_8));
     } finally {
       ctx.close();
     }
@@ -235,7 +236,7 @@ public class SparkSaslSuite {
     final String blockSizeConf = "spark.network.sasl.maxEncryptedBlockSize";
     System.setProperty(blockSizeConf, "1k");
 
-    final AtomicReference<ManagedBuffer> response = new AtomicReference();
+    final AtomicReference<ManagedBuffer> response = new AtomicReference<>();
     final File file = File.createTempFile("sasltest", ".txt");
     SaslTestCtx ctx = null;
     try {
@@ -321,7 +322,8 @@ public class SparkSaslSuite {
     SaslTestCtx ctx = null;
     try {
       ctx = new SaslTestCtx(mock(RpcHandler.class), true, true);
-      ctx.client.sendRpcSync("Ping".getBytes(UTF_8), TimeUnit.SECONDS.toMillis(10));
+      ctx.client.sendRpcSync("Ping".getBytes(StandardCharsets.UTF_8),
+                             TimeUnit.SECONDS.toMillis(10));
       fail("Should have failed to send RPC to server.");
     } catch (Exception e) {
       assertFalse(e.getCause() instanceof TimeoutException);
diff --git a/network/shuffle/src/test/java/org/apache/spark/network/shuffle/ExternalShuffleBlockHandlerSuite.java b/network/shuffle/src/test/java/org/apache/spark/network/shuffle/ExternalShuffleBlockHandlerSuite.java
index 73374cdc77..1d197497b7 100644
--- a/network/shuffle/src/test/java/org/apache/spark/network/shuffle/ExternalShuffleBlockHandlerSuite.java
+++ b/network/shuffle/src/test/java/org/apache/spark/network/shuffle/ExternalShuffleBlockHandlerSuite.java
@@ -90,9 +90,11 @@ public class ExternalShuffleBlockHandlerSuite {
       (StreamHandle) BlockTransferMessage.Decoder.fromByteArray(response.getValue());
     assertEquals(2, handle.numChunks);
 
-    ArgumentCaptor<Iterator> stream = ArgumentCaptor.forClass(Iterator.class);
+    @SuppressWarnings("unchecked")
+    ArgumentCaptor<Iterator<ManagedBuffer>> stream = (ArgumentCaptor<Iterator<ManagedBuffer>>)
+        (ArgumentCaptor<?>) ArgumentCaptor.forClass(Iterator.class);
     verify(streamManager, times(1)).registerStream(stream.capture());
-    Iterator<ManagedBuffer> buffers = (Iterator<ManagedBuffer>) stream.getValue();
+    Iterator<ManagedBuffer> buffers = stream.getValue();
     assertEquals(block0Marker, buffers.next());
     assertEquals(block1Marker, buffers.next());
     assertFalse(buffers.hasNext());
diff --git a/network/shuffle/src/test/java/org/apache/spark/network/shuffle/RetryingBlockFetcherSuite.java b/network/shuffle/src/test/java/org/apache/spark/network/shuffle/RetryingBlockFetcherSuite.java
index 1ad0d72ae5..06e46f9241 100644
--- a/network/shuffle/src/test/java/org/apache/spark/network/shuffle/RetryingBlockFetcherSuite.java
+++ b/network/shuffle/src/test/java/org/apache/spark/network/shuffle/RetryingBlockFetcherSuite.java
@@ -20,7 +20,9 @@ package org.apache.spark.network.shuffle;
 
 import java.io.IOException;
 import java.nio.ByteBuffer;
+import java.util.Arrays;
 import java.util.LinkedHashSet;
+import java.util.List;
 import java.util.Map;
 
 import com.google.common.collect.ImmutableMap;
@@ -67,13 +69,13 @@ public class RetryingBlockFetcherSuite {
   public void testNoFailures() throws IOException {
     BlockFetchingListener listener = mock(BlockFetchingListener.class);
 
-    Map[] interactions = new Map[] {
+    List<? extends Map<String, Object>> interactions = Arrays.asList(
       // Immediately return both blocks successfully.
       ImmutableMap.<String, Object>builder()
         .put("b0", block0)
         .put("b1", block1)
-        .build(),
-    };
+        .build()
+      );
 
     performInteractions(interactions, listener);
 
@@ -86,13 +88,13 @@ public class RetryingBlockFetcherSuite {
   public void testUnrecoverableFailure() throws IOException {
     BlockFetchingListener listener = mock(BlockFetchingListener.class);
 
-    Map[] interactions = new Map[] {
+    List<? extends Map<String, Object>> interactions = Arrays.asList(
       // b0 throws a non-IOException error, so it will be failed without retry.
       ImmutableMap.<String, Object>builder()
         .put("b0", new RuntimeException("Ouch!"))
         .put("b1", block1)
-        .build(),
-    };
+        .build()
+    );
 
     performInteractions(interactions, listener);
 
@@ -105,7 +107,7 @@ public class RetryingBlockFetcherSuite {
   public void testSingleIOExceptionOnFirst() throws IOException {
     BlockFetchingListener listener = mock(BlockFetchingListener.class);
 
-    Map[] interactions = new Map[] {
+    List<? extends Map<String, Object>> interactions = Arrays.asList(
       // IOException will cause a retry. Since b0 fails, we will retry both.
       ImmutableMap.<String, Object>builder()
         .put("b0", new IOException("Connection failed or something"))
@@ -114,8 +116,8 @@ public class RetryingBlockFetcherSuite {
       ImmutableMap.<String, Object>builder()
         .put("b0", block0)
         .put("b1", block1)
-        .build(),
-    };
+        .build()
+    );
 
     performInteractions(interactions, listener);
 
@@ -128,7 +130,7 @@ public class RetryingBlockFetcherSuite {
   public void testSingleIOExceptionOnSecond() throws IOException {
     BlockFetchingListener listener = mock(BlockFetchingListener.class);
 
-    Map[] interactions = new Map[] {
+    List<? extends Map<String, Object>> interactions = Arrays.asList(
       // IOException will cause a retry. Since b1 fails, we will not retry b0.
       ImmutableMap.<String, Object>builder()
         .put("b0", block0)
@@ -136,8 +138,8 @@ public class RetryingBlockFetcherSuite {
         .build(),
       ImmutableMap.<String, Object>builder()
         .put("b1", block1)
-        .build(),
-    };
+        .build()
+    );
 
     performInteractions(interactions, listener);
 
@@ -150,7 +152,7 @@ public class RetryingBlockFetcherSuite {
   public void testTwoIOExceptions() throws IOException {
     BlockFetchingListener listener = mock(BlockFetchingListener.class);
 
-    Map[] interactions = new Map[] {
+    List<? extends Map<String, Object>> interactions = Arrays.asList(
       // b0's IOException will trigger retry, b1's will be ignored.
       ImmutableMap.<String, Object>builder()
         .put("b0", new IOException())
@@ -164,8 +166,8 @@ public class RetryingBlockFetcherSuite {
       // b1 returns successfully within 2 retries.
       ImmutableMap.<String, Object>builder()
         .put("b1", block1)
-        .build(),
-    };
+        .build()
+    );
 
     performInteractions(interactions, listener);
 
@@ -178,7 +180,7 @@ public class RetryingBlockFetcherSuite {
   public void testThreeIOExceptions() throws IOException {
     BlockFetchingListener listener = mock(BlockFetchingListener.class);
 
-    Map[] interactions = new Map[] {
+    List<? extends Map<String, Object>> interactions = Arrays.asList(
       // b0's IOException will trigger retry, b1's will be ignored.
       ImmutableMap.<String, Object>builder()
         .put("b0", new IOException())
@@ -196,8 +198,8 @@ public class RetryingBlockFetcherSuite {
       // This is not reached -- b1 has failed.
       ImmutableMap.<String, Object>builder()
         .put("b1", block1)
-        .build(),
-    };
+        .build()
+    );
 
     performInteractions(interactions, listener);
 
@@ -210,7 +212,7 @@ public class RetryingBlockFetcherSuite {
   public void testRetryAndUnrecoverable() throws IOException {
     BlockFetchingListener listener = mock(BlockFetchingListener.class);
 
-    Map[] interactions = new Map[] {
+    List<? extends Map<String, Object>> interactions = Arrays.asList(
       // b0's IOException will trigger retry, subsequent messages will be ignored.
       ImmutableMap.<String, Object>builder()
         .put("b0", new IOException())
@@ -226,8 +228,8 @@ public class RetryingBlockFetcherSuite {
       // b2 succeeds in its last retry.
       ImmutableMap.<String, Object>builder()
         .put("b2", block2)
-        .build(),
-    };
+        .build()
+    );
 
     performInteractions(interactions, listener);
 
@@ -248,7 +250,8 @@ public class RetryingBlockFetcherSuite {
    * subset of the original blocks in a second interaction.
    */
   @SuppressWarnings("unchecked")
-  private void performInteractions(final Map[] interactions, BlockFetchingListener listener)
+  private static void performInteractions(List<? extends Map<String, Object>> interactions,
+                                          BlockFetchingListener listener)
     throws IOException {
 
     TransportConf conf = new TransportConf(new SystemPropertyConfigProvider());