[SPARK-13583][CORE][STREAMING] Remove unused imports and add checkstyle rule

## What changes were proposed in this pull request? After SPARK-6990, `dev/lint-java` keeps Java code healthy and helps PR review by saving much time. This issue aims remove unused imports from Java/Scala code and add `UnusedImports` checkstyle rule to help developers. ## How was this patch tested? ``` ./dev/lint-java ./build/sbt compile ``` Author: Dongjoon Hyun <dongjoon@apache.org> Closes #11438 from dongjoon-hyun/SPARK-13583.
2016-03-03 10:12:32 +00:00 · 2016-03-03 10:12:32 +00:00 · b5f02d6743
parent e97fc7f176
commit b5f02d6743
226 changed files with 103 additions and 337 deletions
--- a/checkstyle.xml
+++ b/checkstyle.xml
@ -166,5 +166,6 @@
            <property name="exceptionVariableName" value="expected"/>
        </module>
        <module name="CommentsIndentation"/>
+        <module name="UnusedImports"/>
    </module>
 </module>
--- a/common/network-common/src/main/java/org/apache/spark/network/protocol/OneWayMessage.java
+++ b/common/network-common/src/main/java/org/apache/spark/network/protocol/OneWayMessage.java
@ -19,7 +19,6 @@ package org.apache.spark.network.protocol;

 import com.google.common.base.Objects;
 import io.netty.buffer.ByteBuf;
-import io.netty.buffer.Unpooled;

 import org.apache.spark.network.buffer.ManagedBuffer;
 import org.apache.spark.network.buffer.NettyManagedBuffer;
--- a/common/network-common/src/main/java/org/apache/spark/network/protocol/RpcRequest.java
+++ b/common/network-common/src/main/java/org/apache/spark/network/protocol/RpcRequest.java
@ -19,7 +19,6 @@ package org.apache.spark.network.protocol;

 import com.google.common.base.Objects;
 import io.netty.buffer.ByteBuf;
-import io.netty.buffer.Unpooled;

 import org.apache.spark.network.buffer.ManagedBuffer;
 import org.apache.spark.network.buffer.NettyManagedBuffer;
--- a/common/network-common/src/main/java/org/apache/spark/network/protocol/RpcResponse.java
+++ b/common/network-common/src/main/java/org/apache/spark/network/protocol/RpcResponse.java
@ -19,7 +19,6 @@ package org.apache.spark.network.protocol;

 import com.google.common.base.Objects;
 import io.netty.buffer.ByteBuf;
-import io.netty.buffer.Unpooled;

 import org.apache.spark.network.buffer.ManagedBuffer;
 import org.apache.spark.network.buffer.NettyManagedBuffer;
--- a/common/network-common/src/main/java/org/apache/spark/network/protocol/StreamFailure.java
+++ b/common/network-common/src/main/java/org/apache/spark/network/protocol/StreamFailure.java
@ -20,9 +20,6 @@ package org.apache.spark.network.protocol;
 import com.google.common.base.Objects;
 import io.netty.buffer.ByteBuf;

-import org.apache.spark.network.buffer.ManagedBuffer;
-import org.apache.spark.network.buffer.NettyManagedBuffer;
-
 /**
 * Message indicating an error when transferring a stream.
 */
--- a/common/network-common/src/main/java/org/apache/spark/network/protocol/StreamRequest.java
+++ b/common/network-common/src/main/java/org/apache/spark/network/protocol/StreamRequest.java
@ -20,9 +20,6 @@ package org.apache.spark.network.protocol;
 import com.google.common.base.Objects;
 import io.netty.buffer.ByteBuf;

-import org.apache.spark.network.buffer.ManagedBuffer;
-import org.apache.spark.network.buffer.NettyManagedBuffer;
-
 /**
 * Request to stream data from the remote end.
 * <p>
--- a/common/network-common/src/main/java/org/apache/spark/network/protocol/StreamResponse.java
+++ b/common/network-common/src/main/java/org/apache/spark/network/protocol/StreamResponse.java
@ -21,7 +21,6 @@ import com.google.common.base.Objects;
 import io.netty.buffer.ByteBuf;

 import org.apache.spark.network.buffer.ManagedBuffer;
-import org.apache.spark.network.buffer.NettyManagedBuffer;

 /**
 * Response to {@link StreamRequest} when the stream has been successfully opened.
--- a/common/network-common/src/main/java/org/apache/spark/network/sasl/SaslEncryption.java
+++ b/common/network-common/src/main/java/org/apache/spark/network/sasl/SaslEncryption.java
@ -33,7 +33,6 @@ import io.netty.channel.ChannelPromise;
 import io.netty.channel.FileRegion;
 import io.netty.handler.codec.MessageToMessageDecoder;
 import io.netty.util.AbstractReferenceCounted;
-import io.netty.util.ReferenceCountUtil;

 import org.apache.spark.network.util.ByteArrayWritableChannel;
 import org.apache.spark.network.util.NettyUtils;
--- a/common/network-common/src/main/java/org/apache/spark/network/server/TransportRequestHandler.java
+++ b/common/network-common/src/main/java/org/apache/spark/network/server/TransportRequestHandler.java
@ -19,7 +19,6 @@ package org.apache.spark.network.server;

 import java.nio.ByteBuffer;

-import com.google.common.base.Preconditions;
 import com.google.common.base.Throwables;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelFuture;
--- a/common/network-common/src/main/java/org/apache/spark/network/util/NettyUtils.java
+++ b/common/network-common/src/main/java/org/apache/spark/network/util/NettyUtils.java
@ -31,8 +31,6 @@ import io.netty.channel.epoll.EpollSocketChannel;
 import io.netty.channel.nio.NioEventLoopGroup;
 import io.netty.channel.socket.nio.NioServerSocketChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
-import io.netty.handler.codec.ByteToMessageDecoder;
-import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
 import io.netty.util.internal.PlatformDependent;

 /**
--- a/common/network-common/src/main/java/org/apache/spark/network/util/TransportFrameDecoder.java
+++ b/common/network-common/src/main/java/org/apache/spark/network/util/TransportFrameDecoder.java
@ -17,7 +17,6 @@

 package org.apache.spark.network.util;

-import java.util.Iterator;
 import java.util.LinkedList;

 import com.google.common.base.Preconditions;
--- 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
@ -24,7 +24,6 @@ import java.util.concurrent.ConcurrentHashMap;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;

-import org.apache.spark.network.sasl.SecretKeyHolder;
 import org.apache.spark.network.util.JavaUtils;

 /**
--- a/common/network-shuffle/src/test/java/org/apache/spark/network/shuffle/ExternalShuffleSecuritySuite.java
+++ b/common/network-shuffle/src/test/java/org/apache/spark/network/shuffle/ExternalShuffleSecuritySuite.java
@ -30,7 +30,6 @@ import org.apache.spark.network.TestUtils;
 import org.apache.spark.network.TransportContext;
 import org.apache.spark.network.sasl.SaslServerBootstrap;
 import org.apache.spark.network.sasl.SecretKeyHolder;
-import org.apache.spark.network.server.RpcHandler;
 import org.apache.spark.network.server.TransportServer;
 import org.apache.spark.network.server.TransportServerBootstrap;
 import org.apache.spark.network.shuffle.protocol.ExecutorShuffleInfo;
--- a/core/src/main/java/org/apache/spark/shuffle/sort/PackedRecordPointer.java
+++ b/core/src/main/java/org/apache/spark/shuffle/sort/PackedRecordPointer.java
@ -17,8 +17,6 @@

 package org.apache.spark.shuffle.sort;

-import org.apache.spark.memory.TaskMemoryManager;
-
 /**
 * Wrapper around an 8-byte word that holds a 24-bit partition number and 40-bit record pointer.
 * <p>
@ -28,7 +26,7 @@ import org.apache.spark.memory.TaskMemoryManager;
 * </pre>
 * This implies that the maximum addressable page size is 2^27 bits = 128 megabytes, assuming that
 * our offsets in pages are not 8-byte-word-aligned. Since we have 2^13 pages (based off the
- * 13-bit page numbers assigned by {@link TaskMemoryManager}), this
+ * 13-bit page numbers assigned by {@link org.apache.spark.memory.TaskMemoryManager}), this
 * implies that we can address 2^13 * 128 megabytes = 1 terabyte of RAM per task.
 * <p>
 * Assuming word-alignment would allow for a 1 gigabyte maximum page size, but we leave this
--- a/core/src/main/java/org/apache/spark/shuffle/sort/UnsafeShuffleWriter.java
+++ b/core/src/main/java/org/apache/spark/shuffle/sort/UnsafeShuffleWriter.java
@ -25,7 +25,6 @@ import java.util.Iterator;
 import scala.Option;
 import scala.Product2;
 import scala.collection.JavaConverters;
-import scala.collection.immutable.Map;
 import scala.reflect.ClassTag;
 import scala.reflect.ClassTag$;

--- a/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/PrefixComparators.java
+++ b/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/PrefixComparators.java
@ -20,7 +20,6 @@ package org.apache.spark.util.collection.unsafe.sort;
 import com.google.common.primitives.UnsignedLongs;

 import org.apache.spark.annotation.Private;
-import org.apache.spark.unsafe.Platform;
 import org.apache.spark.unsafe.types.ByteArray;
 import org.apache.spark.unsafe.types.UTF8String;
 import org.apache.spark.util.Utils;
--- a/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/RecordPointerAndKeyPrefix.java
+++ b/core/src/main/java/org/apache/spark/util/collection/unsafe/sort/RecordPointerAndKeyPrefix.java
@ -17,11 +17,9 @@

 package org.apache.spark.util.collection.unsafe.sort;

-import org.apache.spark.memory.TaskMemoryManager;
-
 final class RecordPointerAndKeyPrefix {
  /**
-   * A pointer to a record; see {@link TaskMemoryManager} for a
+   * A pointer to a record; see {@link org.apache.spark.memory.TaskMemoryManager} for a
   * description of how these addresses are encoded.
   */
  public long recordPointer;
--- a/core/src/main/scala/org/apache/spark/ExecutorAllocationManager.scala
+++ b/core/src/main/scala/org/apache/spark/ExecutorAllocationManager.scala
@ -26,7 +26,7 @@ import com.codahale.metrics.{Gauge, MetricRegistry}

 import org.apache.spark.metrics.source.Source
 import org.apache.spark.scheduler._
-import org.apache.spark.util.{Clock, SystemClock, ThreadUtils, Utils}
+import org.apache.spark.util.{Clock, SystemClock, ThreadUtils}

 /**
 * An agent that dynamically allocates and removes executors based on the workload.
--- a/core/src/main/scala/org/apache/spark/HeartbeatReceiver.scala
+++ b/core/src/main/scala/org/apache/spark/HeartbeatReceiver.scala
@ -22,7 +22,6 @@ import java.util.concurrent.{ScheduledFuture, TimeUnit}
 import scala.collection.mutable
 import scala.concurrent.Future

-import org.apache.spark.executor.TaskMetrics
 import org.apache.spark.rpc.{RpcCallContext, RpcEnv, ThreadSafeRpcEndpoint}
 import org.apache.spark.scheduler._
 import org.apache.spark.storage.BlockManagerId
--- a/core/src/main/scala/org/apache/spark/Partitioner.scala
+++ b/core/src/main/scala/org/apache/spark/Partitioner.scala
@ -21,13 +21,13 @@ import java.io.{IOException, ObjectInputStream, ObjectOutputStream}

 import scala.collection.mutable
 import scala.collection.mutable.ArrayBuffer
-import scala.reflect.{classTag, ClassTag}
+import scala.reflect.ClassTag
 import scala.util.hashing.byteswap32

 import org.apache.spark.rdd.{PartitionPruningRDD, RDD}
 import org.apache.spark.serializer.JavaSerializer
 import org.apache.spark.util.{CollectionsUtils, Utils}
-import org.apache.spark.util.random.{SamplingUtils, XORShiftRandom}
+import org.apache.spark.util.random.SamplingUtils

 /**
 * An object that defines how the elements in a key-value pair RDD are partitioned by key.
--- a/core/src/main/scala/org/apache/spark/SparkContext.scala
+++ b/core/src/main/scala/org/apache/spark/SparkContext.scala
@ -51,7 +51,6 @@ import org.apache.spark.deploy.{LocalSparkCluster, SparkHadoopUtil}
 import org.apache.spark.input.{FixedLengthBinaryInputFormat, PortableDataStream, StreamInputFormat,
  WholeTextFileInputFormat}
 import org.apache.spark.io.CompressionCodec
-import org.apache.spark.metrics.MetricsSystem
 import org.apache.spark.partial.{ApproximateEvaluator, PartialResult}
 import org.apache.spark.rdd._
 import org.apache.spark.rpc.RpcEndpointRef
--- a/core/src/main/scala/org/apache/spark/TaskNotSerializableException.scala
+++ b/core/src/main/scala/org/apache/spark/TaskNotSerializableException.scala
@ -17,8 +17,6 @@

 package org.apache.spark

-import org.apache.spark.annotation.DeveloperApi
-
 /**
 * Exception thrown when a task cannot be serialized.
 */
--- a/core/src/main/scala/org/apache/spark/api/java/JavaRDD.scala
+++ b/core/src/main/scala/org/apache/spark/api/java/JavaRDD.scala
@ -17,8 +17,6 @@

 package org.apache.spark.api.java

-import java.util.Comparator
-
 import scala.language.implicitConversions
 import scala.reflect.ClassTag

@ -191,7 +189,6 @@ class JavaRDD[T](val rdd: RDD[T])(implicit val classTag: ClassTag[T])
   * Return this RDD sorted by the given key function.
   */
  def sortBy[S](f: JFunction[T, S], ascending: Boolean, numPartitions: Int): JavaRDD[T] = {
-    import scala.collection.JavaConverters._
    def fn: (T) => S = (x: T) => f.call(x)
    import com.google.common.collect.Ordering  // shadows scala.math.Ordering
    implicit val ordering = Ordering.natural().asInstanceOf[Ordering[S]]
--- a/core/src/main/scala/org/apache/spark/broadcast/BroadcastFactory.scala
+++ b/core/src/main/scala/org/apache/spark/broadcast/BroadcastFactory.scala
@ -21,7 +21,6 @@ import scala.reflect.ClassTag

 import org.apache.spark.SecurityManager
 import org.apache.spark.SparkConf
-import org.apache.spark.annotation.DeveloperApi

 /**
 * An interface for all the broadcast implementations in Spark (to allow
--- a/core/src/main/scala/org/apache/spark/deploy/RPackageUtils.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/RPackageUtils.scala
@ -26,7 +26,7 @@ import scala.collection.JavaConverters._

 import com.google.common.io.{ByteStreams, Files}

-import org.apache.spark.{Logging, SparkException}
+import org.apache.spark.Logging
 import org.apache.spark.api.r.RUtils
 import org.apache.spark.util.{RedirectThread, Utils}

--- a/core/src/main/scala/org/apache/spark/deploy/master/DriverInfo.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/master/DriverInfo.scala
@ -19,7 +19,6 @@ package org.apache.spark.deploy.master

 import java.util.Date

-import org.apache.spark.annotation.DeveloperApi
 import org.apache.spark.deploy.DriverDescription
 import org.apache.spark.util.Utils

--- a/core/src/main/scala/org/apache/spark/deploy/worker/Worker.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/worker/Worker.scala
@ -37,7 +37,7 @@ import org.apache.spark.deploy.master.{DriverState, Master}
 import org.apache.spark.deploy.worker.ui.WorkerWebUI
 import org.apache.spark.metrics.MetricsSystem
 import org.apache.spark.rpc._
-import org.apache.spark.util.{SignalLogger, ThreadUtils, Utils}
+import org.apache.spark.util.{ThreadUtils, Utils}

 private[deploy] class Worker(
    override val rpcEnv: RpcEnv,
--- a/core/src/main/scala/org/apache/spark/deploy/worker/ui/LogPage.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/worker/ui/LogPage.scala
@ -18,7 +18,6 @@
 package org.apache.spark.deploy.worker.ui

 import java.io.File
-import java.net.URI
 import javax.servlet.http.HttpServletRequest

 import scala.xml.Node
--- a/core/src/main/scala/org/apache/spark/rdd/DoubleRDDFunctions.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/DoubleRDDFunctions.scala
@ -18,7 +18,6 @@
 package org.apache.spark.rdd

 import org.apache.spark.{Logging, TaskContext}
-import org.apache.spark.annotation.Experimental
 import org.apache.spark.partial.BoundedDouble
 import org.apache.spark.partial.MeanEvaluator
 import org.apache.spark.partial.PartialResult
--- a/core/src/main/scala/org/apache/spark/rdd/JdbcRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/JdbcRDD.scala
@ -17,7 +17,7 @@

 package org.apache.spark.rdd

-import java.sql.{Connection, PreparedStatement, ResultSet}
+import java.sql.{Connection, ResultSet}

 import scala.reflect.ClassTag

--- a/core/src/main/scala/org/apache/spark/rdd/LocalCheckpointRDD.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/LocalCheckpointRDD.scala
@ -19,7 +19,7 @@ package org.apache.spark.rdd

 import scala.reflect.ClassTag

-import org.apache.spark.{Partition, SparkContext, SparkEnv, SparkException, TaskContext}
+import org.apache.spark.{Partition, SparkContext, SparkException, TaskContext}
 import org.apache.spark.storage.RDDBlockId

 /**
--- a/core/src/main/scala/org/apache/spark/rdd/ReliableRDDCheckpointData.scala
+++ b/core/src/main/scala/org/apache/spark/rdd/ReliableRDDCheckpointData.scala
@ -22,7 +22,6 @@ import scala.reflect.ClassTag
 import org.apache.hadoop.fs.Path

 import org.apache.spark._
-import org.apache.spark.util.SerializableConfiguration

 /**
 * An implementation of checkpointing that writes the RDD data to reliable storage.
--- a/core/src/main/scala/org/apache/spark/rpc/netty/NettyRpcEnv.scala
+++ b/core/src/main/scala/org/apache/spark/rpc/netty/NettyRpcEnv.scala
@ -17,7 +17,6 @@
 package org.apache.spark.rpc.netty

 import java.io._
-import java.lang.{Boolean => JBoolean}
 import java.net.{InetSocketAddress, URI}
 import java.nio.ByteBuffer
 import java.nio.channels.{Pipe, ReadableByteChannel, WritableByteChannel}
--- a/core/src/main/scala/org/apache/spark/scheduler/ActiveJob.scala
+++ b/core/src/main/scala/org/apache/spark/scheduler/ActiveJob.scala
@ -19,7 +19,6 @@ package org.apache.spark.scheduler

 import java.util.Properties

-import org.apache.spark.TaskContext
 import org.apache.spark.util.CallSite

 /**
--- a/core/src/main/scala/org/apache/spark/scheduler/DAGSchedulerEvent.scala
+++ b/core/src/main/scala/org/apache/spark/scheduler/DAGSchedulerEvent.scala
@ -19,11 +19,9 @@ package org.apache.spark.scheduler

 import java.util.Properties

-import scala.collection.Map
 import scala.language.existentials

 import org.apache.spark._
-import org.apache.spark.executor.TaskMetrics
 import org.apache.spark.rdd.RDD
 import org.apache.spark.util.CallSite

--- a/core/src/main/scala/org/apache/spark/scheduler/TaskScheduler.scala
+++ b/core/src/main/scala/org/apache/spark/scheduler/TaskScheduler.scala
@ -17,7 +17,6 @@

 package org.apache.spark.scheduler

-import org.apache.spark.executor.TaskMetrics
 import org.apache.spark.scheduler.SchedulingMode.SchedulingMode
 import org.apache.spark.storage.BlockManagerId

--- a/core/src/main/scala/org/apache/spark/scheduler/cluster/CoarseGrainedClusterMessage.scala
+++ b/core/src/main/scala/org/apache/spark/scheduler/cluster/CoarseGrainedClusterMessage.scala
@ -22,7 +22,7 @@ import java.nio.ByteBuffer
 import org.apache.spark.TaskState.TaskState
 import org.apache.spark.rpc.RpcEndpointRef
 import org.apache.spark.scheduler.ExecutorLossReason
-import org.apache.spark.util.{SerializableBuffer, Utils}
+import org.apache.spark.util.SerializableBuffer

 private[spark] sealed trait CoarseGrainedClusterMessage extends Serializable

--- a/core/src/main/scala/org/apache/spark/serializer/Serializer.scala
+++ b/core/src/main/scala/org/apache/spark/serializer/Serializer.scala
@ -23,9 +23,9 @@ import javax.annotation.concurrent.NotThreadSafe

 import scala.reflect.ClassTag

-import org.apache.spark.{SparkConf, SparkEnv}
+import org.apache.spark.SparkEnv
 import org.apache.spark.annotation.{DeveloperApi, Private}
-import org.apache.spark.util.{ByteBufferInputStream, NextIterator, Utils}
+import org.apache.spark.util.NextIterator

 /**
 * :: DeveloperApi ::
--- a/core/src/main/scala/org/apache/spark/shuffle/BaseShuffleHandle.scala
+++ b/core/src/main/scala/org/apache/spark/shuffle/BaseShuffleHandle.scala
@ -17,8 +17,7 @@

 package org.apache.spark.shuffle

-import org.apache.spark.{Aggregator, Partitioner, ShuffleDependency}
-import org.apache.spark.serializer.Serializer
+import org.apache.spark.ShuffleDependency

 /**
 * A basic ShuffleHandle implementation that just captures registerShuffle's parameters.
--- a/core/src/main/scala/org/apache/spark/shuffle/ShuffleBlockResolver.scala
+++ b/core/src/main/scala/org/apache/spark/shuffle/ShuffleBlockResolver.scala
@ -17,8 +17,6 @@

 package org.apache.spark.shuffle

-import java.nio.ByteBuffer
-
 import org.apache.spark.network.buffer.ManagedBuffer
 import org.apache.spark.storage.ShuffleBlockId

--- a/core/src/main/scala/org/apache/spark/shuffle/hash/HashShuffleWriter.scala
+++ b/core/src/main/scala/org/apache/spark/shuffle/hash/HashShuffleWriter.scala
@ -20,7 +20,6 @@ package org.apache.spark.shuffle.hash
 import java.io.IOException

 import org.apache.spark._
-import org.apache.spark.executor.ShuffleWriteMetrics
 import org.apache.spark.scheduler.MapStatus
 import org.apache.spark.serializer.Serializer
 import org.apache.spark.shuffle._
--- a/core/src/main/scala/org/apache/spark/shuffle/sort/SortShuffleWriter.scala
+++ b/core/src/main/scala/org/apache/spark/shuffle/sort/SortShuffleWriter.scala
@ -18,7 +18,6 @@
 package org.apache.spark.shuffle.sort

 import org.apache.spark._
-import org.apache.spark.executor.ShuffleWriteMetrics
 import org.apache.spark.scheduler.MapStatus
 import org.apache.spark.shuffle.{BaseShuffleHandle, IndexShuffleBlockResolver, ShuffleWriter}
 import org.apache.spark.storage.ShuffleBlockId
--- a/core/src/main/scala/org/apache/spark/storage/BlockManagerMaster.scala
+++ b/core/src/main/scala/org/apache/spark/storage/BlockManagerMaster.scala
@ -19,7 +19,7 @@ package org.apache.spark.storage

 import scala.collection.Iterable
 import scala.collection.generic.CanBuildFrom
-import scala.concurrent.{Await, Future}
+import scala.concurrent.Future

 import org.apache.spark.{Logging, SparkConf, SparkException}
 import org.apache.spark.rpc.RpcEndpointRef
--- a/core/src/main/scala/org/apache/spark/storage/DiskStore.scala
+++ b/core/src/main/scala/org/apache/spark/storage/DiskStore.scala
@ -22,7 +22,6 @@ import java.nio.ByteBuffer
 import java.nio.channels.FileChannel.MapMode

 import org.apache.spark.Logging
-import org.apache.spark.serializer.Serializer
 import org.apache.spark.util.Utils

 /**
--- a/core/src/main/scala/org/apache/spark/ui/JettyUtils.scala
+++ b/core/src/main/scala/org/apache/spark/ui/JettyUtils.scala
@ -21,7 +21,7 @@ import java.net.{URI, URL}
 import javax.servlet.DispatcherType
 import javax.servlet.http.{HttpServlet, HttpServletRequest, HttpServletResponse}

-import scala.collection.mutable.{ArrayBuffer, StringBuilder}
+import scala.collection.mutable.ArrayBuffer
 import scala.language.implicitConversions
 import scala.xml.Node

--- a/core/src/main/scala/org/apache/spark/ui/exec/ExecutorThreadDumpPage.scala
+++ b/core/src/main/scala/org/apache/spark/ui/exec/ExecutorThreadDumpPage.scala
@ -19,7 +19,6 @@ package org.apache.spark.ui.exec

 import javax.servlet.http.HttpServletRequest

-import scala.util.Try
 import scala.xml.{Node, Text}

 import org.apache.spark.ui.{UIUtils, WebUIPage}
--- a/core/src/main/scala/org/apache/spark/util/SizeEstimator.scala
+++ b/core/src/main/scala/org/apache/spark/util/SizeEstimator.scala
@ -20,7 +20,6 @@ package org.apache.spark.util
 import java.lang.management.ManagementFactory
 import java.lang.reflect.{Field, Modifier}
 import java.util.{IdentityHashMap, Random}
-import java.util.concurrent.ConcurrentHashMap

 import scala.collection.mutable.ArrayBuffer
 import scala.runtime.ScalaRunTime
--- a/core/src/main/scala/org/apache/spark/util/collection/AppendOnlyMap.scala
+++ b/core/src/main/scala/org/apache/spark/util/collection/AppendOnlyMap.scala
@ -17,7 +17,7 @@

 package org.apache.spark.util.collection

-import java.util.{Arrays, Comparator}
+import java.util.Comparator

 import com.google.common.hash.Hashing

--- a/core/src/test/java/org/apache/spark/launcher/SparkLauncherSuite.java
+++ b/core/src/test/java/org/apache/spark/launcher/SparkLauncherSuite.java
@ -17,9 +17,6 @@

 package org.apache.spark.launcher;

-import java.io.BufferedReader;
-import java.io.InputStream;
-import java.io.InputStreamReader;
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.Map;
--- a/core/src/test/java/org/apache/spark/serializer/TestJavaSerializerImpl.java
+++ b/core/src/test/java/org/apache/spark/serializer/TestJavaSerializerImpl.java
@ -21,7 +21,6 @@ import java.io.InputStream;
 import java.io.OutputStream;
 import java.nio.ByteBuffer;

-import scala.Option;
 import scala.reflect.ClassTag;


--- a/core/src/test/scala/org/apache/spark/MapOutputTrackerSuite.scala
+++ b/core/src/test/scala/org/apache/spark/MapOutputTrackerSuite.scala
@ -22,7 +22,7 @@ import scala.collection.mutable.ArrayBuffer
 import org.mockito.Matchers.{any, isA}
 import org.mockito.Mockito._

-import org.apache.spark.rpc.{RpcAddress, RpcCallContext, RpcEndpointRef, RpcEnv}
+import org.apache.spark.rpc.{RpcAddress, RpcCallContext, RpcEnv}
 import org.apache.spark.scheduler.{CompressedMapStatus, MapStatus}
 import org.apache.spark.shuffle.FetchFailedException
 import org.apache.spark.storage.{BlockManagerId, ShuffleBlockId}
--- a/core/src/test/scala/org/apache/spark/SSLOptionsSuite.scala
+++ b/core/src/test/scala/org/apache/spark/SSLOptionsSuite.scala
@ -20,11 +20,8 @@ package org.apache.spark
 import java.io.File
 import javax.net.ssl.SSLContext

-import com.google.common.io.Files
 import org.scalatest.BeforeAndAfterAll

-import org.apache.spark.util.Utils
-
 class SSLOptionsSuite extends SparkFunSuite with BeforeAndAfterAll {

  test("test resolving property file as spark conf ") {
--- a/core/src/test/scala/org/apache/spark/ThreadingSuite.scala
+++ b/core/src/test/scala/org/apache/spark/ThreadingSuite.scala
@ -17,11 +17,9 @@

 package org.apache.spark

-import java.util.concurrent.{Semaphore, TimeUnit}
+import java.util.concurrent.Semaphore
 import java.util.concurrent.atomic.{AtomicBoolean, AtomicInteger}

-import org.apache.spark.scheduler._
-
 /**
 * Holds state shared across task threads in some ThreadingSuite tests.
 */
--- a/core/src/test/scala/org/apache/spark/deploy/LogUrlsStandaloneSuite.scala
+++ b/core/src/test/scala/org/apache/spark/deploy/LogUrlsStandaloneSuite.scala
@ -22,7 +22,7 @@ import java.net.URL
 import scala.collection.mutable
 import scala.io.Source

-import org.apache.spark.{LocalSparkContext, SparkConf, SparkContext, SparkFunSuite}
+import org.apache.spark.{LocalSparkContext, SparkContext, SparkFunSuite}
 import org.apache.spark.scheduler.{SparkListener, SparkListenerExecutorAdded}
 import org.apache.spark.scheduler.cluster.ExecutorInfo
 import org.apache.spark.util.SparkConfWithEnv
--- a/core/src/test/scala/org/apache/spark/deploy/client/AppClientSuite.scala
+++ b/core/src/test/scala/org/apache/spark/deploy/client/AppClientSuite.scala
@ -19,7 +19,6 @@ package org.apache.spark.deploy.client

 import java.util.concurrent.ConcurrentLinkedQueue

-import scala.collection.JavaConverters._
 import scala.concurrent.duration._

 import org.scalatest.BeforeAndAfterAll
--- a/core/src/test/scala/org/apache/spark/deploy/history/FsHistoryProviderSuite.scala
+++ b/core/src/test/scala/org/apache/spark/deploy/history/FsHistoryProviderSuite.scala
@ -24,16 +24,14 @@ import java.util.concurrent.TimeUnit
 import java.util.zip.{ZipInputStream, ZipOutputStream}

 import scala.concurrent.duration._
-import scala.io.Source
 import scala.language.postfixOps

 import com.google.common.base.Charsets
 import com.google.common.io.{ByteStreams, Files}
-import org.apache.hadoop.fs.Path
 import org.apache.hadoop.hdfs.DistributedFileSystem
 import org.json4s.jackson.JsonMethods._
 import org.mockito.Matchers.any
-import org.mockito.Mockito.{doReturn, mock, spy, verify, when}
+import org.mockito.Mockito.{mock, spy, verify}
 import org.scalatest.BeforeAndAfter
 import org.scalatest.Matchers
 import org.scalatest.concurrent.Eventually._
@ -45,8 +43,6 @@ import org.apache.spark.util.{Clock, JsonProtocol, ManualClock, Utils}

 class FsHistoryProviderSuite extends SparkFunSuite with BeforeAndAfter with Matchers with Logging {

-  import FsHistoryProvider._
-
  private var testDir: File = null

  before {
--- a/core/src/test/scala/org/apache/spark/input/WholeTextFileRecordReaderSuite.scala
+++ b/core/src/test/scala/org/apache/spark/input/WholeTextFileRecordReaderSuite.scala
@ -24,7 +24,7 @@ import java.io.FileOutputStream
 import scala.collection.immutable.IndexedSeq

 import org.apache.hadoop.io.Text
-import org.apache.hadoop.io.compress.{CompressionCodecFactory, DefaultCodec, GzipCodec}
+import org.apache.hadoop.io.compress.{CompressionCodecFactory, GzipCodec}
 import org.scalatest.BeforeAndAfterAll

 import org.apache.spark.{Logging, SparkConf, SparkContext, SparkFunSuite}
--- a/core/src/test/scala/org/apache/spark/launcher/LauncherBackendSuite.scala
+++ b/core/src/test/scala/org/apache/spark/launcher/LauncherBackendSuite.scala
@ -26,7 +26,6 @@ import org.scalatest.Matchers
 import org.scalatest.concurrent.Eventually._

 import org.apache.spark._
-import org.apache.spark.launcher._

 class LauncherBackendSuite extends SparkFunSuite with Matchers {

--- a/core/src/test/scala/org/apache/spark/memory/TestMemoryManager.scala
+++ b/core/src/test/scala/org/apache/spark/memory/TestMemoryManager.scala
@ -17,10 +17,8 @@

 package org.apache.spark.memory

-import scala.collection.mutable
-
 import org.apache.spark.SparkConf
-import org.apache.spark.storage.{BlockId, BlockStatus}
+import org.apache.spark.storage.BlockId

 class TestMemoryManager(conf: SparkConf)
  extends MemoryManager(conf, numCores = 1, Long.MaxValue, Long.MaxValue) {
--- a/core/src/test/scala/org/apache/spark/rpc/RpcEnvSuite.scala
+++ b/core/src/test/scala/org/apache/spark/rpc/RpcEnvSuite.scala
@ -20,7 +20,7 @@ package org.apache.spark.rpc
 import java.io.{File, NotSerializableException}
 import java.nio.charset.StandardCharsets.UTF_8
 import java.util.UUID
-import java.util.concurrent.{ConcurrentLinkedQueue, CountDownLatch, TimeoutException, TimeUnit}
+import java.util.concurrent.{ConcurrentLinkedQueue, CountDownLatch, TimeUnit}

 import scala.collection.mutable
 import scala.collection.JavaConverters._
--- a/core/src/test/scala/org/apache/spark/rpc/netty/InboxSuite.scala
+++ b/core/src/test/scala/org/apache/spark/rpc/netty/InboxSuite.scala
@ -23,7 +23,7 @@ import java.util.concurrent.atomic.AtomicInteger
 import org.mockito.Mockito._

 import org.apache.spark.SparkFunSuite
-import org.apache.spark.rpc.{RpcAddress, RpcEndpoint, RpcEnv, TestRpcEndpoint}
+import org.apache.spark.rpc.{RpcAddress, TestRpcEndpoint}

 class InboxSuite extends SparkFunSuite {

--- a/core/src/test/scala/org/apache/spark/scheduler/cluster/mesos/CoarseMesosSchedulerBackendSuite.scala
+++ b/core/src/test/scala/org/apache/spark/scheduler/cluster/mesos/CoarseMesosSchedulerBackendSuite.scala
@ -33,7 +33,7 @@ import org.scalatest.BeforeAndAfter

 import org.apache.spark.{LocalSparkContext, SecurityManager, SparkConf, SparkContext, SparkFunSuite}
 import org.apache.spark.network.shuffle.mesos.MesosExternalShuffleClient
-import org.apache.spark.rpc.{RpcEndpointRef}
+import org.apache.spark.rpc.RpcEndpointRef
 import org.apache.spark.scheduler.TaskSchedulerImpl

 class CoarseMesosSchedulerBackendSuite extends SparkFunSuite
--- a/core/src/test/scala/org/apache/spark/ui/UISuite.scala
+++ b/core/src/test/scala/org/apache/spark/ui/UISuite.scala
@ -21,7 +21,6 @@ import java.net.{BindException, ServerSocket}

 import scala.io.Source

-import org.eclipse.jetty.server.Server
 import org.eclipse.jetty.servlet.ServletContextHandler
 import org.scalatest.concurrent.Eventually._
 import org.scalatest.time.SpanSugar._
--- a/core/src/test/scala/org/apache/spark/util/ResetSystemProperties.scala
+++ b/core/src/test/scala/org/apache/spark/util/ResetSystemProperties.scala
@ -22,8 +22,6 @@ import java.util.Properties
 import org.apache.commons.lang3.SerializationUtils
 import org.scalatest.{BeforeAndAfterEach, Suite}

-import org.apache.spark.SparkFunSuite
-
 /**
 * Mixin for automatically resetting system properties that are modified in ScalaTest tests.
 * This resets the properties after each individual test.
--- a/core/src/test/scala/org/apache/spark/util/SizeEstimatorSuite.scala
+++ b/core/src/test/scala/org/apache/spark/util/SizeEstimatorSuite.scala
@ -19,7 +19,7 @@ package org.apache.spark.util

 import scala.collection.mutable.ArrayBuffer

-import org.scalatest.{BeforeAndAfterAll, BeforeAndAfterEach, PrivateMethodTester}
+import org.scalatest.{BeforeAndAfterEach, PrivateMethodTester}

 import org.apache.spark.SparkFunSuite

--- a/docker-integration-tests/src/test/scala/org/apache/spark/sql/jdbc/OracleIntegrationSuite.scala
+++ b/docker-integration-tests/src/test/scala/org/apache/spark/sql/jdbc/OracleIntegrationSuite.scala
@ -17,12 +17,10 @@

 package org.apache.spark.sql.jdbc

-import java.math.BigDecimal
-import java.sql.{Connection, Date, Timestamp}
+import java.sql.Connection
 import java.util.Properties

 import org.apache.spark.sql.test.SharedSQLContext
-import org.apache.spark.sql.types._
 import org.apache.spark.tags.DockerTest

 /**
--- a/examples/src/main/java/org/apache/spark/examples/JavaLogQuery.java
+++ b/examples/src/main/java/org/apache/spark/examples/JavaLogQuery.java
@ -28,7 +28,6 @@ import org.apache.spark.api.java.function.Function2;
 import org.apache.spark.api.java.function.PairFunction;

 import java.io.Serializable;
-import java.util.Collections;
 import java.util.List;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
--- a/examples/src/main/java/org/apache/spark/examples/mllib/JavaMultiLabelClassificationMetricsExample.java
+++ b/examples/src/main/java/org/apache/spark/examples/mllib/JavaMultiLabelClassificationMetricsExample.java
@ -25,10 +25,8 @@ import scala.Tuple2;

 import org.apache.spark.api.java.*;
 import org.apache.spark.mllib.evaluation.MultilabelMetrics;
-import org.apache.spark.rdd.RDD;
 import org.apache.spark.SparkConf;
 // $example off$
-import org.apache.spark.SparkContext;

 public class JavaMultiLabelClassificationMetricsExample {
  public static void main(String[] args) {
--- a/examples/src/main/scala/org/apache/spark/examples/DFSReadWriteTest.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/DFSReadWriteTest.scala
@ -23,7 +23,6 @@ import java.io.File
 import scala.io.Source._

 import org.apache.spark.{SparkConf, SparkContext}
-import org.apache.spark.SparkContext._

 /**
  * Simple test for reading and writing to a distributed
--- a/examples/src/main/scala/org/apache/spark/examples/GroupByTest.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/GroupByTest.scala
@ -21,7 +21,6 @@ package org.apache.spark.examples
 import java.util.Random

 import org.apache.spark.{SparkConf, SparkContext}
-import org.apache.spark.SparkContext._

 /**
  * Usage: GroupByTest [numMappers] [numKVPairs] [KeySize] [numReducers]
--- a/examples/src/main/scala/org/apache/spark/examples/LocalKMeans.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/LocalKMeans.scala
@ -25,8 +25,6 @@ import scala.collection.mutable.HashSet

 import breeze.linalg.{squaredDistance, DenseVector, Vector}

-import org.apache.spark.SparkContext._
-
 /**
 * K-means clustering.
 *
--- a/examples/src/main/scala/org/apache/spark/examples/LocalPi.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/LocalPi.scala
@ -20,9 +20,6 @@ package org.apache.spark.examples

 import scala.math.random

-import org.apache.spark._
-import org.apache.spark.SparkContext._
-
 object LocalPi {
  def main(args: Array[String]) {
    var count = 0
--- a/examples/src/main/scala/org/apache/spark/examples/LogQuery.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/LogQuery.scala
@ -19,7 +19,6 @@
 package org.apache.spark.examples

 import org.apache.spark.{SparkConf, SparkContext}
-import org.apache.spark.SparkContext._

 /**
 * Executes a roll up-style query against Apache logs.
--- a/examples/src/main/scala/org/apache/spark/examples/SimpleSkewedGroupByTest.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/SimpleSkewedGroupByTest.scala
@ -21,7 +21,6 @@ package org.apache.spark.examples
 import java.util.Random

 import org.apache.spark.{SparkConf, SparkContext}
-import org.apache.spark.SparkContext._

 /**
  * Usage: SimpleSkewedGroupByTest [numMappers] [numKVPairs] [valSize] [numReducers] [ratio]
--- a/examples/src/main/scala/org/apache/spark/examples/SkewedGroupByTest.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/SkewedGroupByTest.scala
@ -21,7 +21,6 @@ package org.apache.spark.examples
 import java.util.Random

 import org.apache.spark.{SparkConf, SparkContext}
-import org.apache.spark.SparkContext._

 /**
  * Usage: GroupByTest [numMappers] [numKVPairs] [KeySize] [numReducers]
--- a/examples/src/main/scala/org/apache/spark/examples/SparkKMeans.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/SparkKMeans.scala
@ -21,7 +21,6 @@ package org.apache.spark.examples
 import breeze.linalg.{squaredDistance, DenseVector, Vector}

 import org.apache.spark.{SparkConf, SparkContext}
-import org.apache.spark.SparkContext._

 /**
 * K-means clustering.
--- a/examples/src/main/scala/org/apache/spark/examples/SparkPageRank.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/SparkPageRank.scala
@ -19,7 +19,6 @@
 package org.apache.spark.examples

 import org.apache.spark.{SparkConf, SparkContext}
-import org.apache.spark.SparkContext._

 /**
 * Computes the PageRank of URLs from an input file. Input file should
--- a/examples/src/main/scala/org/apache/spark/examples/SparkTC.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/SparkTC.scala
@ -22,7 +22,6 @@ import scala.collection.mutable
 import scala.util.Random

 import org.apache.spark.{SparkConf, SparkContext}
-import org.apache.spark.SparkContext._

 /**
 * Transitive closure on a graph.
--- a/examples/src/main/scala/org/apache/spark/examples/graphx/SynthBenchmark.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/graphx/SynthBenchmark.scala
@ -21,7 +21,6 @@ package org.apache.spark.examples.graphx
 import java.io.{FileOutputStream, PrintWriter}

 import org.apache.spark.{SparkConf, SparkContext}
-import org.apache.spark.SparkContext._
 import org.apache.spark.graphx.{GraphXUtils, PartitionStrategy}
 import org.apache.spark.graphx.util.GraphGenerators

--- a/examples/src/main/scala/org/apache/spark/examples/ml/LinearRegressionExample.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/ml/LinearRegressionExample.scala
@ -18,15 +18,13 @@
 // scalastyle:off println
 package org.apache.spark.examples.ml

-import scala.collection.mutable
 import scala.language.reflectiveCalls

 import scopt.OptionParser

 import org.apache.spark.{SparkConf, SparkContext}
 import org.apache.spark.examples.mllib.AbstractParams
-import org.apache.spark.ml.{Pipeline, PipelineStage}
-import org.apache.spark.ml.regression.{LinearRegression, LinearRegressionModel}
+import org.apache.spark.ml.regression.LinearRegression
 import org.apache.spark.sql.DataFrame

 /**
--- a/examples/src/main/scala/org/apache/spark/examples/mllib/CosineSimilarity.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/mllib/CosineSimilarity.scala
@ -21,7 +21,6 @@ package org.apache.spark.examples.mllib
 import scopt.OptionParser

 import org.apache.spark.{SparkConf, SparkContext}
-import org.apache.spark.SparkContext._
 import org.apache.spark.mllib.linalg.Vectors
 import org.apache.spark.mllib.linalg.distributed.{MatrixEntry, RowMatrix}

--- a/examples/src/main/scala/org/apache/spark/examples/mllib/MovieLensALS.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/mllib/MovieLensALS.scala
@ -24,7 +24,6 @@ import org.apache.log4j.{Level, Logger}
 import scopt.OptionParser

 import org.apache.spark.{SparkConf, SparkContext}
-import org.apache.spark.SparkContext._
 import org.apache.spark.mllib.recommendation.{ALS, MatrixFactorizationModel, Rating}
 import org.apache.spark.rdd.RDD

--- a/examples/src/main/scala/org/apache/spark/examples/mllib/SampledRDDs.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/mllib/SampledRDDs.scala
@ -21,7 +21,6 @@ package org.apache.spark.examples.mllib
 import scopt.OptionParser

 import org.apache.spark.{SparkConf, SparkContext}
-import org.apache.spark.SparkContext._
 import org.apache.spark.mllib.util.MLUtils

 /**
--- a/examples/src/main/scala/org/apache/spark/examples/streaming/ActorWordCount.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/streaming/ActorWordCount.scala
@ -19,7 +19,6 @@
 package org.apache.spark.examples.streaming

 import scala.collection.mutable.LinkedHashSet
-import scala.reflect.ClassTag
 import scala.util.Random

 import akka.actor._
--- a/examples/src/main/scala/org/apache/spark/examples/streaming/CustomReceiver.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/streaming/CustomReceiver.scala
@ -18,7 +18,7 @@
 // scalastyle:off println
 package org.apache.spark.examples.streaming

-import java.io.{BufferedReader, InputStream, InputStreamReader}
+import java.io.{BufferedReader, InputStreamReader}
 import java.net.Socket

 import org.apache.spark.{Logging, SparkConf}
--- a/examples/src/main/scala/org/apache/spark/examples/streaming/FlumePollingEventCount.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/streaming/FlumePollingEventCount.scala
@ -18,10 +18,7 @@
 // scalastyle:off println
 package org.apache.spark.examples.streaming

-import java.net.InetSocketAddress
-
 import org.apache.spark.SparkConf
-import org.apache.spark.storage.StorageLevel
 import org.apache.spark.streaming._
 import org.apache.spark.streaming.flume._
 import org.apache.spark.util.IntParam
--- a/examples/src/main/scala/org/apache/spark/examples/streaming/SqlNetworkWordCount.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/streaming/SqlNetworkWordCount.scala
@ -24,7 +24,6 @@ import org.apache.spark.rdd.RDD
 import org.apache.spark.sql.SQLContext
 import org.apache.spark.storage.StorageLevel
 import org.apache.spark.streaming.{Seconds, StreamingContext, Time}
-import org.apache.spark.util.IntParam

 /**
 * Use DataFrames and SQL to count words in UTF8 encoded, '\n' delimited text received from the
--- a/examples/src/main/scala/org/apache/spark/examples/streaming/StatefulNetworkWordCount.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/streaming/StatefulNetworkWordCount.scala
@ -18,7 +18,6 @@
 // scalastyle:off println
 package org.apache.spark.examples.streaming

-import org.apache.spark.HashPartitioner
 import org.apache.spark.SparkConf
 import org.apache.spark.streaming._

--- a/examples/src/main/scala/org/apache/spark/examples/streaming/TwitterAlgebirdCMS.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/streaming/TwitterAlgebirdCMS.scala
@ -22,7 +22,6 @@ import com.twitter.algebird._
 import com.twitter.algebird.CMSHasherImplicits._

 import org.apache.spark.SparkConf
-import org.apache.spark.SparkContext._
 import org.apache.spark.storage.StorageLevel
 import org.apache.spark.streaming.{Seconds, StreamingContext}
 import org.apache.spark.streaming.twitter._
--- a/examples/src/main/scala/org/apache/spark/examples/streaming/TwitterPopularTags.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/streaming/TwitterPopularTags.scala
@ -19,7 +19,6 @@
 package org.apache.spark.examples.streaming

 import org.apache.spark.streaming.{Seconds, StreamingContext}
-import org.apache.spark.SparkContext._
 import org.apache.spark.streaming.twitter._
 import org.apache.spark.SparkConf

--- a/examples/src/main/scala/org/apache/spark/examples/streaming/ZeroMQWordCount.scala
+++ b/examples/src/main/scala/org/apache/spark/examples/streaming/ZeroMQWordCount.scala
@ -25,9 +25,8 @@ import akka.actor.actorRef2Scala
 import akka.util.ByteString
 import akka.zeromq._
 import akka.zeromq.Subscribe
-import com.typesafe.config.ConfigFactory

-import org.apache.spark.{SparkConf, TaskContext}
+import org.apache.spark.SparkConf
 import org.apache.spark.streaming.{Seconds, StreamingContext}
 import org.apache.spark.streaming.zeromq._

--- a/external/flume/src/test/scala/org/apache/spark/streaming/TestOutputStream.scala
+++ b/external/flume/src/test/scala/org/apache/spark/streaming/TestOutputStream.scala
@ -20,7 +20,6 @@ package org.apache.spark.streaming
 import java.io.{IOException, ObjectInputStream}
 import java.util.concurrent.ConcurrentLinkedQueue

-import scala.collection.mutable.ArrayBuffer
 import scala.reflect.ClassTag

 import org.apache.spark.rdd.RDD
--- a/external/mqtt/src/test/scala/org/apache/spark/streaming/mqtt/MQTTStreamSuite.scala
+++ b/external/mqtt/src/test/scala/org/apache/spark/streaming/mqtt/MQTTStreamSuite.scala
@ -23,7 +23,7 @@ import scala.language.postfixOps
 import org.scalatest.BeforeAndAfter
 import org.scalatest.concurrent.Eventually

-import org.apache.spark.{SparkConf, SparkFunSuite}
+import org.apache.spark.SparkFunSuite
 import org.apache.spark.storage.StorageLevel
 import org.apache.spark.streaming.{Milliseconds, StreamingContext}

--- a/external/twitter/src/main/scala/org/apache/spark/streaming/twitter/TwitterUtils.scala
+++ b/external/twitter/src/main/scala/org/apache/spark/streaming/twitter/TwitterUtils.scala
@ -22,8 +22,8 @@ import twitter4j.auth.Authorization

 import org.apache.spark.storage.StorageLevel
 import org.apache.spark.streaming.StreamingContext
-import org.apache.spark.streaming.api.java.{JavaDStream, JavaReceiverInputDStream, JavaStreamingContext}
-import org.apache.spark.streaming.dstream.{DStream, ReceiverInputDStream}
+import org.apache.spark.streaming.api.java.{JavaReceiverInputDStream, JavaStreamingContext}
+import org.apache.spark.streaming.dstream.ReceiverInputDStream

 object TwitterUtils {
  /**
--- a/graphx/src/main/scala/org/apache/spark/graphx/GraphOps.scala
+++ b/graphx/src/main/scala/org/apache/spark/graphx/GraphOps.scala
@ -17,15 +17,10 @@

 package org.apache.spark.graphx

-import scala.reflect.{classTag, ClassTag}
 import scala.reflect.ClassTag
 import scala.util.Random

-import org.apache.spark.HashPartitioner
-import org.apache.spark.SparkContext._
 import org.apache.spark.SparkException
-import org.apache.spark.graphx.impl.EdgePartitionBuilder
-import org.apache.spark.graphx.impl.GraphImpl
 import org.apache.spark.graphx.lib._
 import org.apache.spark.rdd.RDD

--- a/graphx/src/main/scala/org/apache/spark/graphx/VertexRDD.scala
+++ b/graphx/src/main/scala/org/apache/spark/graphx/VertexRDD.scala
@ -20,7 +20,6 @@ package org.apache.spark.graphx
 import scala.reflect.ClassTag

 import org.apache.spark._
-import org.apache.spark.SparkContext._
 import org.apache.spark.graphx.impl.RoutingTablePartition
 import org.apache.spark.graphx.impl.ShippableVertexPartition
 import org.apache.spark.graphx.impl.VertexAttributeBlock
--- a/graphx/src/main/scala/org/apache/spark/graphx/impl/EdgePartition.scala
+++ b/graphx/src/main/scala/org/apache/spark/graphx/impl/EdgePartition.scala
@ -17,7 +17,7 @@

 package org.apache.spark.graphx.impl

-import scala.reflect.{classTag, ClassTag}
+import scala.reflect.ClassTag

 import org.apache.spark.graphx._
 import org.apache.spark.graphx.util.collection.GraphXPrimitiveKeyOpenHashMap
--- a/graphx/src/main/scala/org/apache/spark/graphx/impl/ReplicatedVertexView.scala
+++ b/graphx/src/main/scala/org/apache/spark/graphx/impl/ReplicatedVertexView.scala
@ -17,9 +17,8 @@

 package org.apache.spark.graphx.impl

-import scala.reflect.{classTag, ClassTag}
+import scala.reflect.ClassTag

-import org.apache.spark.SparkContext._
 import org.apache.spark.graphx._
 import org.apache.spark.rdd.RDD

--- a/graphx/src/main/scala/org/apache/spark/graphx/impl/RoutingTablePartition.scala
+++ b/graphx/src/main/scala/org/apache/spark/graphx/impl/RoutingTablePartition.scala
@ -17,14 +17,8 @@

 package org.apache.spark.graphx.impl

-import scala.reflect.ClassTag
-
-import org.apache.spark.Partitioner
 import org.apache.spark.graphx._
-import org.apache.spark.graphx.impl.RoutingTablePartition.RoutingTableMessage
 import org.apache.spark.graphx.util.collection.GraphXPrimitiveKeyOpenHashMap
-import org.apache.spark.rdd.RDD
-import org.apache.spark.rdd.ShuffledRDD
 import org.apache.spark.util.collection.{BitSet, PrimitiveVector}

 private[graphx]
--- a/graphx/src/main/scala/org/apache/spark/graphx/impl/VertexPartition.scala
+++ b/graphx/src/main/scala/org/apache/spark/graphx/impl/VertexPartition.scala
@ -20,7 +20,6 @@ package org.apache.spark.graphx.impl
 import scala.reflect.ClassTag

 import org.apache.spark.graphx._
-import org.apache.spark.graphx.util.collection.GraphXPrimitiveKeyOpenHashMap
 import org.apache.spark.util.collection.BitSet

 private[graphx] object VertexPartition {
--- a/Show more
+++ b/Show more