Java HTTP Port Find findUnusedPort(int preferredPort)

Description

Find and return an unused server socket port.

License

Open Source License

Parameter

Parameter	Description
preferredPort	a parameter

Declaration

public static int findUnusedPort(int preferredPort) 

Method Source Code

//package com.java2s;
/*//from  w  w w.j av a  2 s. c  o m
 * Copyright (c) 2012, the Dart project authors.
 * 
 * Licensed under the Eclipse Public License v1.0 (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.eclipse.org/legal/epl-v10.html
 * 
 * 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 {
    /**
     * Find and return an unused server socket port. Attempt to use preferredPort; if that is not
     * available then we return any unused port.
     * 
     * @param preferredPort
     * @return
     */
    public static int findUnusedPort(int preferredPort) {
        try {
            // Bind to any free port.
            ServerSocket ss = new ServerSocket(0);

            int port = ss.getLocalPort();

            ss.close();

            return port;
        } catch (IOException ioe) {

        }

        return -1;
    }
}

Related

1. findFreePort(int startPort)
2. findFreePortExcepting(int portToExclude)
3. findFreePortForApi()
4. findUnusedPort()
5. findUnusedPort()
6. findUnusedPorts(int numPorts)
7. freePort()
8. freePort()
9. freePort()