Here you can find the source of isTcpPortOpen(int port)
public static boolean isTcpPortOpen(int port)
//package com.java2s; /******************************************************************************* * This file is part of OpenNMS(R).//from www. ja va 2 s . c o m * * Copyright (C) 2016 The OpenNMS Group, Inc. * OpenNMS(R) is Copyright (C) 1999-2016 The OpenNMS Group, Inc. * * OpenNMS(R) is a registered trademark of The OpenNMS Group, Inc. * * OpenNMS(R) is free software: you can redistribute it and/or modify * it under the terms of the GNU Affero General Public License as published * by the Free Software Foundation, either version 3 of the License, * or (at your option) any later version. * * OpenNMS(R) is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Affero General Public License for more details. * * You should have received a copy of the GNU Affero General Public License * along with OpenNMS(R). If not, see: * http://www.gnu.org/licenses/ * * For more information contact: * OpenNMS(R) Licensing <license@opennms.org> * http://www.opennms.org/ * http://www.opennms.com/ *******************************************************************************/ import java.net.InetSocketAddress; import java.net.Socket; public class Main { public static boolean isTcpPortOpen(int port) { return isTcpPortOpen(new InetSocketAddress("127.0.0.1", port)); } public static boolean isTcpPortOpen(InetSocketAddress addr) { try (Socket socket = new Socket()) { socket.connect(addr, 100); return true; } catch (Exception ex) { return false; } } }