How do I close sockets?

You should always close the output and input stream before you close the socket.

On the client side:

try {
output.close();
input.close();
MyClient.close();
}
catch (IOException e) {
System.out.println(e);
}

On the server side:

try {
output.close();
input.close();
serviceSocket.close();
MyService.close();
}
catch (IOException e) {
System.out.println(e);
}