In SimpleSocketServer.run, the ServerSocket constructor is invoked directly to create a new server socket. This makes it difficult for a subclass to have any influence over the creation of server sockets (e.g. to use an SSL server socket).

If SimpleSocketServer declared a method such as this:

protected ServerSocketFactory getServerSocketFactory() {
return ServerSocketFactory.getDefault()
}

and used it in the run() implementation...

...
serverSocket = getServerSocketFactory().createSocket(port);
...

then a subclass could override it with, for example, an appropriately configured SSLServerSocketFactory...

public class MySSLSimpleSocketServer extends SimpleSocketServer {
...
protected ServerSocketFactory getServerSocketFactory()

{ return mySslContext.getServerSocketFactory(); }

...
}