TestResourceTrackerService fail intermittently on jdk7

Tests run: 6, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 1.73 sec <<< FAILURE!
testDecommissionWithIncludeHosts(org.apache.hadoop.yarn.server.resourcemanager.TestResourceTrackerService) Time elapsed: 0.086 sec <<< FAILURE!
junit.framework.AssertionFailedError: expected:<0> but was:<1> at junit.framework.Assert.fail(Assert.java:47)
at junit.framework.Assert.failNotEquals(Assert.java:283)
at junit.framework.Assert.assertEquals(Assert.java:64)
at junit.framework.Assert.assertEquals(Assert.java:195)
at junit.framework.Assert.assertEquals(Assert.java:201)
at org.apache.hadoop.yarn.server.resourcemanager.TestResourceTrackerService.testDecommissionWithIncludeHosts(TestResourceTrackerService.java:90)