/*
 * 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.
 */

package org.apache.commons.vfs2.util;

import java.io.IOException;
import java.net.ServerSocket;

public class FreeSocketPortUtil
{

    public static void main(final String[] args) throws IOException
    {
        System.out.println(FreeSocketPortUtil.findFreeLocalPort());
    }

    /**
     * Finds a free local socket port.
     *
     * @return a free local socket port.
     * @throws IOException
     */
    public static int findFreeLocalPort() throws IOException
    {
        final ServerSocket server = new ServerSocket(0);
        try
        {
            return server.getLocalPort();
        } finally
        {
            server.close();
        }
    }
}

/*
 * 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.
 */

package org.apache.commons.vfs2.util;

import java.io.IOException;
import java.net.ServerSocket;

public class FreeSocketPortUtil {

    public static void main(final String[] args) throws IOException {
        System.out.println(FreeSocketPortUtil.findFreeLocalPort());
    }

    /**
     * Finds a free local socket port.
     *
     * @return a free local socket port.
     * @throws IOException
     */
    public static int findFreeLocalPort() throws IOException {
        try (final ServerSocket server = new ServerSocket(0)) {
            return server.getLocalPort();
        }
    }
}

Use try-with-resources.