YARN-8977. Remove unnecessary type casting when calling AbstractYarnScheduler#getSchedulerNode. Contributed by Wanqiang Ji.

(cherry picked from commit c96cbe8659587cfc114a96aab1be5cc85029fe44)

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/CapacityScheduler.java

@@ -2189,8 +2189,8 @@ public class CapacityScheduler extends
         super.completedContainer(killableContainer, SchedulerUtils
             .createPreemptedContainerStatus(killableContainer.getContainerId(),
                 SchedulerUtils.PREEMPTED_CONTAINER), RMContainerEventType.KILL);
-      } else{
-        FiCaSchedulerNode node = (FiCaSchedulerNode) getSchedulerNode(
+      } else {
+        FiCaSchedulerNode node = getSchedulerNode(
             killableContainer.getAllocatedNode());
 
         FiCaSchedulerApp application = getCurrentAttemptForContainer(
@@ -2222,7 +2222,7 @@ public class CapacityScheduler extends
                 + nonKillableContainer.toString());
       }
 
-      FiCaSchedulerNode node = (FiCaSchedulerNode) getSchedulerNode(
+      FiCaSchedulerNode node = getSchedulerNode(
           nonKillableContainer.getAllocatedNode());
 
       FiCaSchedulerApp application = getCurrentAttemptForContainer(

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/TestContinuousScheduling.java

@@ -376,8 +376,7 @@ public class TestContinuousScheduling extends FairSchedulerTestBase {
 
     NodeAddedSchedulerEvent nodeEvent1 = new NodeAddedSchedulerEvent(node1);
     scheduler.handle(nodeEvent1);
-    FSSchedulerNode node =
-        (FSSchedulerNode) scheduler.getSchedulerNode(node1.getNodeID());
+    FSSchedulerNode node = scheduler.getSchedulerNode(node1.getNodeID());
     // Tick the time and let the fsApp startTime different from initScheduler
     // time
     mockClock.tickSec(delayThresholdTimeMs / 1000);

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/TestFairScheduler.java

@@ -4557,8 +4557,7 @@ public class TestFairScheduler extends FairSchedulerTestBase {
     NodeAddedSchedulerEvent nodeEvent1 = new NodeAddedSchedulerEvent(node1);
     scheduler.handle(nodeEvent1);
 
-    FSSchedulerNode node = (FSSchedulerNode)scheduler.getSchedulerNode(
-      node1.getNodeID());
+    FSSchedulerNode node = scheduler.getSchedulerNode(node1.getNodeID());
 
     NodeRemovedSchedulerEvent removeNode1 =
         new NodeRemovedSchedulerEvent(node1);