Use the interface when possible

git-svn-id: https://svn.apache.org/repos/asf/cxf/trunk@1531410 13f79535-47bb-0310-9956-ffa450edef68
Fix compile failures

git-svn-id: https://svn.apache.org/repos/asf/cxf/trunk@1531411 13f79535-47bb-0310-9956-ffa450edef68