* Add maven-javadoc-plugin to all Java clients.
* Update sample petstores for other Java clients.
* Fix unknown parameter on api_client's update_params_for_auth method.
* Revert "Fix unknown parameter on api_client's update_params_for_auth method."
To be moved to a separate PR.
This reverts commit 1ee186694241bb6d9a0dccefcdca5afe3f5a1dd2.