fix style

core/src/main/java/org/apache/spark/memory/TaskMemoryManager.java

@@ -412,7 +412,7 @@ public long getMemoryConsumptionForThisTask() {
   /**
    * Returns Tungsten memory mode
    */
-  public MemoryMode getTungstenMemoryMode(){
+  public MemoryMode getTungstenMemoryMode() {
     return tungstenMemoryMode;
   }
 }

core/src/main/scala/org/apache/spark/util/collection/ExternalAppendOnlyMap.scala

@@ -584,7 +584,7 @@ class ExternalAppendOnlyMap[K, V, C](
           s"it will release ${org.apache.spark.util.Utils.bytesToString(getUsed())} memory")
         nextUpstream = spillMemoryIteratorToDisk(upstream)
         hasSpilled = true
-         true
+        true
       }
     }
 

core/src/main/scala/org/apache/spark/util/collection/Spillable.scala

@@ -40,7 +40,7 @@ private[spark] abstract class Spillable[C](taskMemoryManager: TaskMemoryManager)
   protected def forceSpill(): Boolean
 
   // Number of elements read from input since last spill
-  @volatile protected def elementsRead: Long = _elementsRead
+  protected def elementsRead: Long = _elementsRead
 
   // Called by subclasses every time a record is read
   // It's used for checking spilling frequency
@@ -61,7 +61,7 @@ private[spark] abstract class Spillable[C](taskMemoryManager: TaskMemoryManager)
   @volatile private[this] var myMemoryThreshold = initialMemoryThreshold
 
   // Number of elements read from input since last spill
-  private[this] var _elementsRead = 0L
+  @volatile private[this] var _elementsRead = 0L
 
   // Number of bytes spilled in total
   @volatile private[this] var _memoryBytesSpilled = 0L