Socket: java.net.BindException: Address already in use

java.net.BindException: Address already in use
        at java.net.PlainSocketImpl.socketBind(Native Method)
        at java.net.AbstractPlainSocketImpl.bind(AbstractPlainSocketImpl.java:376)
        at java.net.ServerSocket.bind(ServerSocket.java:376)

When you disconnect a socket connection and immediately use the same IP address and port number for a new socket, this exception may throw. This is because when a TCP connection is closed, the connection may remain in a timeout state for a period of time after the connection is closed, also known as the TIME_WAIT state or 2MSL wait state. It may not be possible to bind a socket to the requred socket address if there is a connection in the timeout state involving the socket address or port. However, setting the reuse address of the socket to true before binding allows the socket to be bound even though a previous connection is in a timeout state.

For example, the following code throws the exception.

      ServerSocket serverSocket = new ServerSocket(<port>);

The following code will not throw the exception.

      ServerSocket serverSocket = new ServerSocket();
      serverSocket.setReuseAddress(true);
      serverSocket.bind(new InetSocketAddress(<port>));

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