[SPARK-14011][CORE][SQL] Enable `LineLength` Java checkstyle rule

## What changes were proposed in this pull request?

[Spark Coding Style Guide](https://cwiki.apache.org/confluence/display/SPARK/Spark+Code+Style+Guide) has 100-character limit on lines, but it's disabled for Java since 11/09/15. This PR enables **LineLength** checkstyle again. To help that, this also introduces **RedundantImport** and **RedundantModifier**, too. The following is the diff on `checkstyle.xml`.

```xml
-        <!-- TODO: 11/09/15 disabled - the lengths are currently > 100 in many places -->
-        <!--
         <module name="LineLength">
             <property name="max" value="100"/>
             <property name="ignorePattern" value="^package.*|^import.*|a href|href|http://|https://|ftp://"/>
         </module>
-        -->
         <module name="NoLineWrap"/>
         <module name="EmptyBlock">
             <property name="option" value="TEXT"/>
 -167,5 +164,7
         </module>
         <module name="CommentsIndentation"/>
         <module name="UnusedImports"/>
+        <module name="RedundantImport"/>
+        <module name="RedundantModifier"/>
```

## How was this patch tested?

Currently, `lint-java` is disabled in Jenkins. It needs a manual test.
After passing the Jenkins tests, `dev/lint-java` should passes locally.

Author: Dongjoon Hyun <dongjoon@apache.org>

Closes #11831 from dongjoon-hyun/SPARK-14011.

7 files changed, 12 insertions, 8 deletions

diff --git a/common/network-shuffle/src/main/java/org/apache/spark/network/sasl/ShuffleSecretManager.java b/common/network-shuffle/src/main/java/org/apache/spark/network/sasl/ShuffleSecretManager.java
index cdce297233..268cb40121 100644
--- a/common/network-shuffle/src/main/java/org/apache/spark/network/sasl/ShuffleSecretManager.java
+++ b/common/network-shuffle/src/main/java/org/apache/spark/network/sasl/ShuffleSecretManager.java
@@ -17,7 +17,6 @@
 
 package org.apache.spark.network.sasl;
 
-import java.lang.Override;
 import java.nio.ByteBuffer;
 import java.util.concurrent.ConcurrentHashMap;
 
diff --git a/common/network-shuffle/src/main/java/org/apache/spark/network/shuffle/ExternalShuffleBlockHandler.java b/common/network-shuffle/src/main/java/org/apache/spark/network/shuffle/ExternalShuffleBlockHandler.java
index f22187a01d..f8d03b3b94 100644
--- a/common/network-shuffle/src/main/java/org/apache/spark/network/shuffle/ExternalShuffleBlockHandler.java
+++ b/common/network-shuffle/src/main/java/org/apache/spark/network/shuffle/ExternalShuffleBlockHandler.java
@@ -52,7 +52,8 @@ public class ExternalShuffleBlockHandler extends RpcHandler {
   final ExternalShuffleBlockResolver blockManager;
   private final OneForOneStreamManager streamManager;
 
-  public ExternalShuffleBlockHandler(TransportConf conf, File registeredExecutorFile) throws IOException {
+  public ExternalShuffleBlockHandler(TransportConf conf, File registeredExecutorFile)
+    throws IOException {
     this(new OneForOneStreamManager(),
       new ExternalShuffleBlockResolver(conf, registeredExecutorFile));
   }
diff --git a/common/network-shuffle/src/main/java/org/apache/spark/network/shuffle/ExternalShuffleBlockResolver.java b/common/network-shuffle/src/main/java/org/apache/spark/network/shuffle/ExternalShuffleBlockResolver.java
index 460110d78f..ce5c68e853 100644
--- a/common/network-shuffle/src/main/java/org/apache/spark/network/shuffle/ExternalShuffleBlockResolver.java
+++ b/common/network-shuffle/src/main/java/org/apache/spark/network/shuffle/ExternalShuffleBlockResolver.java
@@ -423,7 +423,9 @@ public class ExternalShuffleBlockResolver {
     public final int major;
     public final int minor;
 
-    @JsonCreator public StoreVersion(@JsonProperty("major") int major, @JsonProperty("minor") int minor) {
+    @JsonCreator public StoreVersion(
+      @JsonProperty("major") int major,
+      @JsonProperty("minor") int minor) {
       this.major = major;
       this.minor = minor;
     }
diff --git a/common/network-shuffle/src/main/java/org/apache/spark/network/shuffle/RetryingBlockFetcher.java b/common/network-shuffle/src/main/java/org/apache/spark/network/shuffle/RetryingBlockFetcher.java
index 4bb0498e5d..d81cf869dd 100644
--- a/common/network-shuffle/src/main/java/org/apache/spark/network/shuffle/RetryingBlockFetcher.java
+++ b/common/network-shuffle/src/main/java/org/apache/spark/network/shuffle/RetryingBlockFetcher.java
@@ -46,7 +46,7 @@ public class RetryingBlockFetcher {
    * Used to initiate the first fetch for all blocks, and subsequently for retrying the fetch on any
    * remaining blocks.
    */
-  public static interface BlockFetchStarter {
+  public interface BlockFetchStarter {
     /**
      * Creates a new BlockFetcher to fetch the given block ids which may do some synchronous
      * bootstrapping followed by fully asynchronous block fetching.
diff --git a/common/network-shuffle/src/main/java/org/apache/spark/network/shuffle/protocol/BlockTransferMessage.java b/common/network-shuffle/src/main/java/org/apache/spark/network/shuffle/protocol/BlockTransferMessage.java
index 21c0ff4136..9af6759f5d 100644
--- a/common/network-shuffle/src/main/java/org/apache/spark/network/shuffle/protocol/BlockTransferMessage.java
+++ b/common/network-shuffle/src/main/java/org/apache/spark/network/shuffle/protocol/BlockTransferMessage.java
@@ -40,13 +40,13 @@ public abstract class BlockTransferMessage implements Encodable {
   protected abstract Type type();
 
   /** Preceding every serialized message is its type, which allows us to deserialize it. */
-  public static enum Type {
+  public enum Type {
     OPEN_BLOCKS(0), UPLOAD_BLOCK(1), REGISTER_EXECUTOR(2), STREAM_HANDLE(3), REGISTER_DRIVER(4),
     HEARTBEAT(5);
 
     private final byte id;
 
-    private Type(int id) {
+    Type(int id) {
       assert id < 128 : "Cannot have more than 128 message types";
       this.id = (byte) id;
     }
diff --git a/common/network-shuffle/src/test/java/org/apache/spark/network/sasl/SaslIntegrationSuite.java b/common/network-shuffle/src/test/java/org/apache/spark/network/sasl/SaslIntegrationSuite.java
index 5322fcd781..5bf9924185 100644
--- a/common/network-shuffle/src/test/java/org/apache/spark/network/sasl/SaslIntegrationSuite.java
+++ b/common/network-shuffle/src/test/java/org/apache/spark/network/sasl/SaslIntegrationSuite.java
@@ -212,7 +212,8 @@ public class SaslIntegrationSuite {
       };
 
       String[] blockIds = { "shuffle_2_3_4", "shuffle_6_7_8" };
-      OneForOneBlockFetcher fetcher = new OneForOneBlockFetcher(client1, "app-2", "0", blockIds, listener);
+      OneForOneBlockFetcher fetcher =
+          new OneForOneBlockFetcher(client1, "app-2", "0", blockIds, listener);
       fetcher.start();
       blockFetchLatch.await();
       checkSecurityException(exception.get());
diff --git a/common/network-shuffle/src/test/java/org/apache/spark/network/shuffle/ExternalShuffleBlockHandlerSuite.java b/common/network-shuffle/src/test/java/org/apache/spark/network/shuffle/ExternalShuffleBlockHandlerSuite.java
index 9379412155..c2e0b7447f 100644
--- a/common/network-shuffle/src/test/java/org/apache/spark/network/shuffle/ExternalShuffleBlockHandlerSuite.java
+++ b/common/network-shuffle/src/test/java/org/apache/spark/network/shuffle/ExternalShuffleBlockHandlerSuite.java
@@ -113,7 +113,8 @@ public class ExternalShuffleBlockHandlerSuite {
       // pass
     }
 
-    ByteBuffer unexpectedMsg = new UploadBlock("a", "e", "b", new byte[1], new byte[2]).toByteBuffer();
+    ByteBuffer unexpectedMsg = new UploadBlock("a", "e", "b", new byte[1],
+      new byte[2]).toByteBuffer();
     try {
       handler.receive(client, unexpectedMsg, callback);
       fail("Should have thrown");