From e6f99e205b1922c296486a5e23f2764f016207d1 Mon Sep 17 00:00:00 2001
From: Takanobu Asanuma <tasanuma@yahoo-corp.jp>
Date: Tue, 6 Mar 2018 06:01:33 -0800
Subject: [PATCH] HADOOP-15291. TestMiniKdc fails on Java 9

Signed-off-by: Akira Ajisaka <aajisaka@apache.org>
---
 .../src/test/java/org/apache/hadoop/minikdc/TestMiniKdc.java   | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/hadoop-common-project/hadoop-minikdc/src/test/java/org/apache/hadoop/minikdc/TestMiniKdc.java b/hadoop-common-project/hadoop-minikdc/src/test/java/org/apache/hadoop/minikdc/TestMiniKdc.java
index dafa1c1ea62..204f65666a7 100644
--- a/hadoop-common-project/hadoop-minikdc/src/test/java/org/apache/hadoop/minikdc/TestMiniKdc.java
+++ b/hadoop-common-project/hadoop-minikdc/src/test/java/org/apache/hadoop/minikdc/TestMiniKdc.java
@@ -165,7 +165,8 @@ public class TestMiniKdc extends KerberosSecurityTestcase {
       loginContext.logout();
 
     } finally {
-      if (loginContext != null) {
+      if (loginContext != null && loginContext.getSubject() != null
+          && !loginContext.getSubject().getPrincipals().isEmpty()) {
         loginContext.logout();
       }
     }