Added documentation.


git-svn-id: https://svn.apache.org/repos/asf/sis/branches/JDK8@1635791 13f79535-47bb-0310-9956-ffa450edef68
Added test.


git-svn-id: https://svn.apache.org/repos/asf/sis/branches/JDK8@1635792 13f79535-47bb-0310-9956-ffa450edef68