Made method public

git-svn-id: https://svn.apache.org/repos/asf/maven/shared/trunk@1631468 13f79535-47bb-0310-9956-ffa450edef68
Added some @Nullables

git-svn-id: https://svn.apache.org/repos/asf/maven/shared/trunk@1631470 13f79535-47bb-0310-9956-ffa450edef68