HADOOP-8751. NPE in Token.toString() when Token is constructed using null identifier. Contributed by kanaka kumar avvaru.

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -752,6 +752,9 @@ Release 2.8.0 - UNRELEASED
     HADOOP-11927.  Fix "undefined reference to dlopen" error when compiling
     libhadooppipes (Xianyin Xin via Colin P. McCabe)
 
+    HADOOP-8751. NPE in Token.toString() when Token is constructed using null
+    identifier. (kanaka kumar avvaru via aajisaka)
+
 Release 2.7.1 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/token/Token.java

@@ -70,10 +70,10 @@ public class Token<T extends TokenIdentifier> implements Writable {
    * @param service the service for this token
    */
   public Token(byte[] identifier, byte[] password, Text kind, Text service) {
-    this.identifier = identifier;
-    this.password = password;
-    this.kind = kind;
-    this.service = service;
+    this.identifier = (identifier == null)? new byte[0] : identifier;
+    this.password = (password == null)? new byte[0] : password;
+    this.kind = (kind == null)? new Text() : kind;
+    this.service = (service == null)? new Text() : service;
   }
 
   /**

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/security/token/delegation/TestDelegationToken.java

@@ -44,6 +44,7 @@ import org.apache.hadoop.security.UserGroupInformation.AuthenticationMethod;
 import org.apache.hadoop.security.token.SecretManager;
 import org.apache.hadoop.security.token.Token;
 import org.apache.hadoop.security.token.SecretManager.InvalidToken;
+import org.apache.hadoop.security.token.TokenIdentifier;
 import org.apache.hadoop.security.token.delegation.AbstractDelegationTokenSecretManager.DelegationTokenInformation;
 import org.apache.hadoop.util.Daemon;
 import org.apache.hadoop.util.Time;
@@ -539,4 +540,18 @@ public class TestDelegationToken {
     Assert.assertEquals(key1, key2);
     Assert.assertFalse(key2.equals(key3));
   }
+
+  @Test
+  public void testEmptyToken() throws IOException {
+    Token<?> token1 = new Token<TokenIdentifier>();
+
+    Token<?> token2 = new Token<TokenIdentifier>(new byte[0], new byte[0],
+        new Text(), new Text());
+    assertEquals(token1, token2);
+    assertEquals(token1.encodeToUrlString(), token2.encodeToUrlString());
+
+    token2 = new Token<TokenIdentifier>(null, null, null, null);
+    assertEquals(token1, token2);
+    assertEquals(token1.encodeToUrlString(), token2.encodeToUrlString());
+  }
 }