Java Socket Port getFreeSocketPort()

Description

Return a free port number.

License

Apache License

Declaration

public static int getFreeSocketPort() 

Method Source Code

//package com.java2s;
/**/*from w w  w .j  a  v a  2s. c  o m*/
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.io.IOException;

import java.net.ServerSocket;

public class Main {
    /**
     * Return a free port number. There is no guarantee it will remain free, so
     * it should be used immediately.
     *
     * @returns A free port for binding a local socket
     */
    public static int getFreeSocketPort() {
        int port = 0;
        try {
            ServerSocket s = new ServerSocket(0);
            port = s.getLocalPort();
            s.close();
            return port;
        } catch (IOException e) {
            // Could not get a free port. Return default port 0.
        }
        return port;
    }
}

Related

1. getHostPort(Socket s)
2. getMyPortNumber(ServerSocket serverSocket)
3. getPort(ServerSocket server)
4. getRandomPortServerSocket()