[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.

2 files changed, 8 insertions, 10 deletions

diff --git a/mllib/src/test/java/org/apache/spark/mllib/evaluation/JavaRankingMetricsSuite.java b/mllib/src/test/java/org/apache/spark/mllib/evaluation/JavaRankingMetricsSuite.java
index effc8a1a6d..fa4d334801 100644
--- a/mllib/src/test/java/org/apache/spark/mllib/evaluation/JavaRankingMetricsSuite.java
+++ b/mllib/src/test/java/org/apache/spark/mllib/evaluation/JavaRankingMetricsSuite.java
@@ -18,12 +18,12 @@
 package org.apache.spark.mllib.evaluation;
 
 import java.io.Serializable;
-import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
 
 import scala.Tuple2;
 import scala.Tuple2$;
 
-import com.google.common.collect.Lists;
 import org.junit.After;
 import org.junit.Assert;
 import org.junit.Before;
@@ -34,18 +34,18 @@ import org.apache.spark.api.java.JavaSparkContext;
 
 public class JavaRankingMetricsSuite implements Serializable {
   private transient JavaSparkContext sc;
-  private transient JavaRDD<Tuple2<ArrayList<Integer>, ArrayList<Integer>>> predictionAndLabels;
+  private transient JavaRDD<Tuple2<List<Integer>, List<Integer>>> predictionAndLabels;
 
   @Before
   public void setUp() {
     sc = new JavaSparkContext("local", "JavaRankingMetricsSuite");
-    predictionAndLabels = sc.parallelize(Lists.newArrayList(
+    predictionAndLabels = sc.parallelize(Arrays.asList(
       Tuple2$.MODULE$.apply(
-        Lists.newArrayList(1, 6, 2, 7, 8, 3, 9, 10, 4, 5), Lists.newArrayList(1, 2, 3, 4, 5)),
+        Arrays.asList(1, 6, 2, 7, 8, 3, 9, 10, 4, 5), Arrays.asList(1, 2, 3, 4, 5)),
       Tuple2$.MODULE$.apply(
-        Lists.newArrayList(4, 1, 5, 6, 2, 7, 3, 8, 9, 10), Lists.newArrayList(1, 2, 3)),
+          Arrays.asList(4, 1, 5, 6, 2, 7, 3, 8, 9, 10), Arrays.asList(1, 2, 3)),
       Tuple2$.MODULE$.apply(
-        Lists.newArrayList(1, 2, 3, 4, 5), Lists.<Integer>newArrayList())), 2);
+          Arrays.asList(1, 2, 3, 4, 5), Arrays.<Integer>asList())), 2);
   }
 
   @After
diff --git a/mllib/src/test/scala/org/apache/spark/ml/classification/NaiveBayesSuite.scala b/mllib/src/test/scala/org/apache/spark/ml/classification/NaiveBayesSuite.scala
index aea3d9b694..98bc951116 100644
--- a/mllib/src/test/scala/org/apache/spark/ml/classification/NaiveBayesSuite.scala
+++ b/mllib/src/test/scala/org/apache/spark/ml/classification/NaiveBayesSuite.scala
@@ -21,7 +21,7 @@ import breeze.linalg.{Vector => BV}
 
 import org.apache.spark.SparkFunSuite
 import org.apache.spark.ml.param.ParamsSuite
-import org.apache.spark.mllib.classification.NaiveBayes
+import org.apache.spark.mllib.classification.NaiveBayes.{Multinomial, Bernoulli}
 import org.apache.spark.mllib.linalg._
 import org.apache.spark.mllib.util.MLlibTestSparkContext
 import org.apache.spark.mllib.util.TestingUtils._
@@ -31,8 +31,6 @@ import org.apache.spark.sql.Row
 
 class NaiveBayesSuite extends SparkFunSuite with MLlibTestSparkContext {
 
-  import NaiveBayes.{Multinomial, Bernoulli}
-
   def validatePrediction(predictionAndLabels: DataFrame): Unit = {
     val numOfErrorPredictions = predictionAndLabels.collect().count {
       case Row(prediction: Double, label: Double) =>