[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.

12 files changed, 47 insertions, 34 deletions

diff --git a/examples/src/main/java/org/apache/spark/examples/JavaPageRank.java b/examples/src/main/java/org/apache/spark/examples/JavaPageRank.java
index c3ef93c5b6..229d123441 100644
--- a/examples/src/main/java/org/apache/spark/examples/JavaPageRank.java
+++ b/examples/src/main/java/org/apache/spark/examples/JavaPageRank.java
@@ -84,13 +84,14 @@ public final class JavaPageRank {
     JavaRDD<String> lines = ctx.textFile(args[0], 1);
 
     // Loads all URLs from input file and initialize their neighbors.
-    JavaPairRDD<String, Iterable<String>> links = lines.mapToPair(new PairFunction<String, String, String>() {
-      @Override
-      public Tuple2<String, String> call(String s) {
-        String[] parts = SPACES.split(s);
-        return new Tuple2<>(parts[0], parts[1]);
-      }
-    }).distinct().groupByKey().cache();
+    JavaPairRDD<String, Iterable<String>> links = lines.mapToPair(
+      new PairFunction<String, String, String>() {
+        @Override
+        public Tuple2<String, String> call(String s) {
+          String[] parts = SPACES.split(s);
+          return new Tuple2<>(parts[0], parts[1]);
+        }
+      }).distinct().groupByKey().cache();
 
     // Loads all URLs with other URL(s) link to from input file and initialize ranks of them to one.
     JavaPairRDD<String, Double> ranks = links.mapValues(new Function<Iterable<String>, Double>() {
diff --git a/examples/src/main/java/org/apache/spark/examples/JavaWordCount.java b/examples/src/main/java/org/apache/spark/examples/JavaWordCount.java
index 84dbea5caa..3ff5412b93 100644
--- a/examples/src/main/java/org/apache/spark/examples/JavaWordCount.java
+++ b/examples/src/main/java/org/apache/spark/examples/JavaWordCount.java
@@ -52,19 +52,21 @@ public final class JavaWordCount {
       }
     });
 
-    JavaPairRDD<String, Integer> ones = words.mapToPair(new PairFunction<String, String, Integer>() {
-      @Override
-      public Tuple2<String, Integer> call(String s) {
-        return new Tuple2<>(s, 1);
-      }
-    });
+    JavaPairRDD<String, Integer> ones = words.mapToPair(
+      new PairFunction<String, String, Integer>() {
+        @Override
+        public Tuple2<String, Integer> call(String s) {
+          return new Tuple2<>(s, 1);
+        }
+      });
 
-    JavaPairRDD<String, Integer> counts = ones.reduceByKey(new Function2<Integer, Integer, Integer>() {
-      @Override
-      public Integer call(Integer i1, Integer i2) {
-        return i1 + i2;
-      }
-    });
+    JavaPairRDD<String, Integer> counts = ones.reduceByKey(
+      new Function2<Integer, Integer, Integer>() {
+        @Override
+        public Integer call(Integer i1, Integer i2) {
+          return i1 + i2;
+        }
+      });
 
     List<Tuple2<String, Integer>> output = counts.collect();
     for (Tuple2<?,?> tuple : output) {
diff --git a/examples/src/main/java/org/apache/spark/examples/ml/JavaDecisionTreeClassificationExample.java b/examples/src/main/java/org/apache/spark/examples/ml/JavaDecisionTreeClassificationExample.java
index 5bd61fe508..8214952f80 100644
--- a/examples/src/main/java/org/apache/spark/examples/ml/JavaDecisionTreeClassificationExample.java
+++ b/examples/src/main/java/org/apache/spark/examples/ml/JavaDecisionTreeClassificationExample.java
@@ -39,7 +39,10 @@ public class JavaDecisionTreeClassificationExample {
 
     // $example on$
     // Load the data stored in LIBSVM format as a DataFrame.
-    Dataset<Row> data = sqlContext.read().format("libsvm").load("data/mllib/sample_libsvm_data.txt");
+    Dataset<Row> data = sqlContext
+      .read()
+      .format("libsvm")
+      .load("data/mllib/sample_libsvm_data.txt");
 
     // Index labels, adding metadata to the label column.
     // Fit on whole dataset to include all labels in index.
diff --git a/examples/src/main/java/org/apache/spark/examples/ml/JavaDeveloperApiExample.java b/examples/src/main/java/org/apache/spark/examples/ml/JavaDeveloperApiExample.java
index 8a10dd48aa..fbd8817669 100644
--- a/examples/src/main/java/org/apache/spark/examples/ml/JavaDeveloperApiExample.java
+++ b/examples/src/main/java/org/apache/spark/examples/ml/JavaDeveloperApiExample.java
@@ -107,11 +107,11 @@ public class JavaDeveloperApiExample {
 class MyJavaLogisticRegression
   extends Classifier<Vector, MyJavaLogisticRegression, MyJavaLogisticRegressionModel> {
 
-  public MyJavaLogisticRegression() {
+  MyJavaLogisticRegression() {
     init();
   }
 
-  public MyJavaLogisticRegression(String uid) {
+  MyJavaLogisticRegression(String uid) {
     this.uid_ = uid;
     init();
   }
@@ -177,7 +177,7 @@ class MyJavaLogisticRegressionModel
   private Vector coefficients_;
   public Vector coefficients() { return coefficients_; }
 
-  public MyJavaLogisticRegressionModel(String uid, Vector coefficients) {
+  MyJavaLogisticRegressionModel(String uid, Vector coefficients) {
     this.uid_ = uid;
     this.coefficients_ = coefficients;
   }
diff --git a/examples/src/main/java/org/apache/spark/examples/ml/JavaGradientBoostedTreeClassifierExample.java b/examples/src/main/java/org/apache/spark/examples/ml/JavaGradientBoostedTreeClassifierExample.java
index c2cb955385..553070dace 100644
--- a/examples/src/main/java/org/apache/spark/examples/ml/JavaGradientBoostedTreeClassifierExample.java
+++ b/examples/src/main/java/org/apache/spark/examples/ml/JavaGradientBoostedTreeClassifierExample.java
@@ -40,7 +40,8 @@ public class JavaGradientBoostedTreeClassifierExample {
 
     // $example on$
     // Load and parse the data file, converting it to a DataFrame.
-    Dataset<Row> data = sqlContext.read().format("libsvm").load("data/mllib/sample_libsvm_data.txt");
+    Dataset<Row> data = sqlContext.read().format("libsvm")
+      .load("data/mllib/sample_libsvm_data.txt");
 
     // Index labels, adding metadata to the label column.
     // Fit on whole dataset to include all labels in index.
diff --git a/examples/src/main/java/org/apache/spark/examples/mllib/JavaBinaryClassificationMetricsExample.java b/examples/src/main/java/org/apache/spark/examples/mllib/JavaBinaryClassificationMetricsExample.java
index 3d8babba04..7561a1f653 100644
--- a/examples/src/main/java/org/apache/spark/examples/mllib/JavaBinaryClassificationMetricsExample.java
+++ b/examples/src/main/java/org/apache/spark/examples/mllib/JavaBinaryClassificationMetricsExample.java
@@ -65,7 +65,8 @@ public class JavaBinaryClassificationMetricsExample {
     );
 
     // Get evaluation metrics.
-    BinaryClassificationMetrics metrics = new BinaryClassificationMetrics(predictionAndLabels.rdd());
+    BinaryClassificationMetrics metrics =
+      new BinaryClassificationMetrics(predictionAndLabels.rdd());
 
     // Precision by threshold
     JavaRDD<Tuple2<Object, Object>> precision = metrics.precisionByThreshold().toJavaRDD();
diff --git a/examples/src/main/java/org/apache/spark/examples/mllib/JavaIsotonicRegressionExample.java b/examples/src/main/java/org/apache/spark/examples/mllib/JavaIsotonicRegressionExample.java
index 0e15f75508..c6361a3729 100644
--- a/examples/src/main/java/org/apache/spark/examples/mllib/JavaIsotonicRegressionExample.java
+++ b/examples/src/main/java/org/apache/spark/examples/mllib/JavaIsotonicRegressionExample.java
@@ -48,7 +48,8 @@ public class JavaIsotonicRegressionExample {
     );
 
     // Split data into training (60%) and test (40%) sets.
-    JavaRDD<Tuple3<Double, Double, Double>>[] splits = parsedData.randomSplit(new double[]{0.6, 0.4}, 11L);
+    JavaRDD<Tuple3<Double, Double, Double>>[] splits =
+        parsedData.randomSplit(new double[]{0.6, 0.4}, 11L);
     JavaRDD<Tuple3<Double, Double, Double>> training = splits[0];
     JavaRDD<Tuple3<Double, Double, Double>> test = splits[1];
 
@@ -80,7 +81,8 @@ public class JavaIsotonicRegressionExample {
 
     // Save and load model
     model.save(jsc.sc(), "target/tmp/myIsotonicRegressionModel");
-    IsotonicRegressionModel sameModel = IsotonicRegressionModel.load(jsc.sc(), "target/tmp/myIsotonicRegressionModel");
+    IsotonicRegressionModel sameModel =
+      IsotonicRegressionModel.load(jsc.sc(), "target/tmp/myIsotonicRegressionModel");
     // $example off$
 
     jsc.stop();
diff --git a/examples/src/main/java/org/apache/spark/examples/mllib/JavaStreamingTestExample.java b/examples/src/main/java/org/apache/spark/examples/mllib/JavaStreamingTestExample.java
index 4c8755916c..984909cb94 100644
--- a/examples/src/main/java/org/apache/spark/examples/mllib/JavaStreamingTestExample.java
+++ b/examples/src/main/java/org/apache/spark/examples/mllib/JavaStreamingTestExample.java
@@ -18,7 +18,6 @@
 package org.apache.spark.examples.mllib;
 
 
-import org.apache.spark.Accumulator;
 import org.apache.spark.api.java.function.VoidFunction;
 import org.apache.spark.api.java.JavaRDD;
 import org.apache.spark.api.java.function.Function;
diff --git a/examples/src/main/java/org/apache/spark/examples/streaming/JavaDirectKafkaWordCount.java b/examples/src/main/java/org/apache/spark/examples/streaming/JavaDirectKafkaWordCount.java
index bfbad91e4f..769b21cecf 100644
--- a/examples/src/main/java/org/apache/spark/examples/streaming/JavaDirectKafkaWordCount.java
+++ b/examples/src/main/java/org/apache/spark/examples/streaming/JavaDirectKafkaWordCount.java
@@ -40,7 +40,8 @@ import org.apache.spark.streaming.Durations;
  *   <topics> is a list of one or more kafka topics to consume from
  *
  * Example:
- *    $ bin/run-example streaming.JavaDirectKafkaWordCount broker1-host:port,broker2-host:port topic1,topic2
+ *    $ bin/run-example streaming.JavaDirectKafkaWordCount broker1-host:port,broker2-host:port \
+ *      topic1,topic2
  */
 
 public final class JavaDirectKafkaWordCount {
diff --git a/examples/src/main/java/org/apache/spark/examples/streaming/JavaQueueStream.java b/examples/src/main/java/org/apache/spark/examples/streaming/JavaQueueStream.java
index 426eaa5f0a..62413b4606 100644
--- a/examples/src/main/java/org/apache/spark/examples/streaming/JavaQueueStream.java
+++ b/examples/src/main/java/org/apache/spark/examples/streaming/JavaQueueStream.java
@@ -30,7 +30,6 @@ import org.apache.spark.SparkConf;
 import org.apache.spark.api.java.JavaRDD;
 import org.apache.spark.api.java.function.Function2;
 import org.apache.spark.api.java.function.PairFunction;
-import org.apache.spark.examples.streaming.StreamingExamples;
 import org.apache.spark.streaming.Duration;
 import org.apache.spark.streaming.api.java.JavaDStream;
 import org.apache.spark.streaming.api.java.JavaPairDStream;
diff --git a/examples/src/main/java/org/apache/spark/examples/streaming/JavaRecoverableNetworkWordCount.java b/examples/src/main/java/org/apache/spark/examples/streaming/JavaRecoverableNetworkWordCount.java
index a597ecbc5b..e5fb2bfbfa 100644
--- a/examples/src/main/java/org/apache/spark/examples/streaming/JavaRecoverableNetworkWordCount.java
+++ b/examples/src/main/java/org/apache/spark/examples/streaming/JavaRecoverableNetworkWordCount.java
@@ -155,9 +155,11 @@ public final class JavaRecoverableNetworkWordCount {
       @Override
       public void call(JavaPairRDD<String, Integer> rdd, Time time) throws IOException {
         // Get or register the blacklist Broadcast
-        final Broadcast<List<String>> blacklist = JavaWordBlacklist.getInstance(new JavaSparkContext(rdd.context()));
+        final Broadcast<List<String>> blacklist =
+            JavaWordBlacklist.getInstance(new JavaSparkContext(rdd.context()));
         // Get or register the droppedWordsCounter Accumulator
-        final Accumulator<Integer> droppedWordsCounter = JavaDroppedWordsCounter.getInstance(new JavaSparkContext(rdd.context()));
+        final Accumulator<Integer> droppedWordsCounter =
+            JavaDroppedWordsCounter.getInstance(new JavaSparkContext(rdd.context()));
         // Use blacklist to drop words and use droppedWordsCounter to count them
         String counts = rdd.filter(new Function<Tuple2<String, Integer>, Boolean>() {
           @Override
@@ -210,7 +212,8 @@ public final class JavaRecoverableNetworkWordCount {
       }
     };
 
-    JavaStreamingContext ssc = JavaStreamingContext.getOrCreate(checkpointDirectory, createContextFunc);
+    JavaStreamingContext ssc =
+      JavaStreamingContext.getOrCreate(checkpointDirectory, createContextFunc);
     ssc.start();
     ssc.awaitTermination();
   }
diff --git a/examples/src/main/java/org/apache/spark/examples/streaming/JavaStatefulNetworkWordCount.java b/examples/src/main/java/org/apache/spark/examples/streaming/JavaStatefulNetworkWordCount.java
index 6beab90f08..4230dab52e 100644
--- a/examples/src/main/java/org/apache/spark/examples/streaming/JavaStatefulNetworkWordCount.java
+++ b/examples/src/main/java/org/apache/spark/examples/streaming/JavaStatefulNetworkWordCount.java
@@ -91,7 +91,8 @@ public class JavaStatefulNetworkWordCount {
     Function3<String, Optional<Integer>, State<Integer>, Tuple2<String, Integer>> mappingFunc =
         new Function3<String, Optional<Integer>, State<Integer>, Tuple2<String, Integer>>() {
           @Override
-          public Tuple2<String, Integer> call(String word, Optional<Integer> one, State<Integer> state) {
+          public Tuple2<String, Integer> call(String word, Optional<Integer> one,
+              State<Integer> state) {
             int sum = one.orElse(0) + (state.exists() ? state.get() : 0);
             Tuple2<String, Integer> output = new Tuple2<>(word, sum);
             state.update(sum);