Socket getPort vs getLocalPort

The getLocalPort() method returns the port to which the socket binds to. Whereas the getPort() method returns the remote port to which the socket connects to.

For example

ServerSocket serverSocket = new ServerSocket(6045, 50, <InetAddress>);

You create a Socket using the serverSocket's InetAddress and port number to connect to it. You may use this socket to read and write or you can also use the socket returned by serverSocket.accept() to read and write. However, they have different local and remote ports.

A. Using the created socket

Socket socket = new Socket(<InetAddress>, 6045);
socket.getPort() will return the port number used in the above line which is 6045. socket.getLocalPort will return something else, lets say 53222.

To this socket, the server is remote.

B. Using the accepted socket

Socket socket2 = serverSocket.accept();
socket2.getPort() will return 53222 and socket2.getLocalPort() will return 6045.

To this socket2, the server is local.

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