correct number of tasks in ExecutorsUI

core/src/main/scala/org/apache/spark/ui/exec/ExecutorsUI.scala

@@ -100,15 +100,16 @@ private[spark] class ExecutorsUI(val sc: SparkContext) {
   }
 
   def getExecInfo(a: Int): Seq[String] = {
-    val execId = sc.getExecutorStorageStatus(a).blockManagerId.executorId
-    val hostPort = sc.getExecutorStorageStatus(a).blockManagerId.hostPort
-    val rddBlocks = sc.getExecutorStorageStatus(a).blocks.size.toString
-    val memUsed = sc.getExecutorStorageStatus(a).memUsed().toString
-    val maxMem = sc.getExecutorStorageStatus(a).maxMem.toString
-    val diskUsed = sc.getExecutorStorageStatus(a).diskUsed().toString
-    val activeTasks = listener.executorToTasksActive.get(a.toString).map(l => l.size).getOrElse(0)
-    val failedTasks = listener.executorToTasksFailed.getOrElse(a.toString, 0)
-    val completedTasks = listener.executorToTasksComplete.getOrElse(a.toString, 0)
+    val status = sc.getExecutorStorageStatus(a)
+    val execId = status.blockManagerId.executorId
+    val hostPort = status.blockManagerId.hostPort
+    val rddBlocks = status.blocks.size.toString
+    val memUsed = status.memUsed().toString
+    val maxMem = status.maxMem.toString
+    val diskUsed = status.diskUsed().toString
+    val activeTasks = listener.executorToTasksActive.getOrElse(execId, Seq[Long]()).size
+    val failedTasks = listener.executorToTasksFailed.getOrElse(execId, 0)
+    val completedTasks = listener.executorToTasksComplete.getOrElse(execId, 0)
     val totalTasks = activeTasks + failedTasks + completedTasks
 
     Seq(