Fixed a NullPointerException.


git-svn-id: https://svn.apache.org/repos/asf/sis/branches/JDK8@1605685 13f79535-47bb-0310-9956-ffa450edef68
Merged the NullPointerException fix.


git-svn-id: https://svn.apache.org/repos/asf/sis/branches/JDK7@1605686 13f79535-47bb-0310-9956-ffa450edef68