YARN-8548. AllocationRespose proto setNMToken initBuilder not done. Contributed by Bilwa S T.

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/api/protocolrecords/impl/pb/AllocateResponsePBImpl.java

@@ -347,6 +347,7 @@ public class AllocateResponsePBImpl extends AllocateResponse {
 
   @Override
   public synchronized void setNMTokens(List<NMToken> nmTokens) {
+    maybeInitBuilder();
     if (nmTokens == null || nmTokens.isEmpty()) {
       if (this.nmTokens != null) {
         this.nmTokens.clear();

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/recovery/TestProtos.java

@@ -18,7 +18,15 @@
 
 package org.apache.hadoop.yarn.server.resourcemanager.recovery;
 
+import static org.junit.Assert.*;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.hadoop.yarn.api.protocolrecords.impl.pb.AllocateResponsePBImpl;
+import org.apache.hadoop.yarn.api.records.NMToken;
 import org.apache.hadoop.yarn.proto.YarnServerResourceManagerRecoveryProtos.EpochProto;
+import org.apache.hadoop.yarn.proto.YarnServiceProtos.AllocateResponseProto;
 import org.junit.Assert;
 import org.junit.Test;
 
@@ -33,4 +41,16 @@ public class TestProtos {
     String protoString = proto.toString();
     Assert.assertNotNull(protoString);
   }
+
+  @Test
+  public void testProtoAllocateResponse() {
+    AllocateResponseProto proto = AllocateResponseProto.getDefaultInstance();
+    AllocateResponsePBImpl alloc = new AllocateResponsePBImpl(proto);
+    List<NMToken> nmTokens = new ArrayList<NMToken>();
+    try {
+      alloc.setNMTokens(nmTokens);
+    } catch (Exception ex) {
+      fail();
+    }
+  }
 }