Add missing javadoc.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/lang/trunk@1448286 13f79535-47bb-0310-9956-ffa450edef68
Add missing javadoc.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/lang/trunk@1448287 13f79535-47bb-0310-9956-ffa450edef68