If the Client that gets a remote Connection (WrapperDataSourceService) does not close it properly (sloppy or crash), it will never be released again.
This can be solved rather easily, the finalize method of the Server part of the proxy should call close.

Thus if the client object gets garbage collected (or the JVM dies), the server object (proxy) will be garbage collected and the finalize method called.

This thing is that a sloppy or crashing client can occupy all available connections, leaving all other applications with no connection to work with.