minor improvement and javadoc

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1440613 13f79535-47bb-0310-9956-ffa450edef68
minor improvement

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1440614 13f79535-47bb-0310-9956-ffa450edef68