Backport findbugs configuration to 4.3 so we can run a findbugs report in jenkins.
nullpointer dereference guarded
moved call on static object to synchronized block
restored imports
Fix findbug issues within LDAP authenticator
Findbugs issues in ApiResponseHelper fixes
findbugs fixes for ApiServer, ApiSerializerHelper and ApiXmlDocWriter
findbugs: retrieve the objects to remove from the collection(s)
findbugs: null-checks
Findbugs: different issues solved
findbugs: nullpointer guards and wrappertype comparisons