Java example source code file (KeepAliveTimerThread.java)

This example Java source code file (KeepAliveTimerThread.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

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Java - Java tags/keywords

body, exception, fetcher, html, inputstream, ioexception, mygroup, net, network, printstream, runnable, server, serversocket, string, thread, threadgroup

The KeepAliveTimerThread.java Java example source code

/*
 * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/*
 * @test
 * @bug 4701299
 * @summary Keep-Alive-Timer thread management in KeepAliveCache causes memory leak
 */
import java.net.*;
import java.io.*;

public class KeepAliveTimerThread {
    static class Fetcher implements Runnable {
        String url;

        Fetcher(String url) {
            this.url = url;
        }

        public void run() {
            try {
                InputStream in =
                    (new URL(url)).openConnection().getInputStream();
                byte b[] = new byte[128];
                int n;
                do {
                    n = in.read(b);
                } while (n > 0);
                in.close();
            } catch (Exception x) {
                x.printStackTrace();
            }
        }
    }

    static class Server extends Thread {
        ServerSocket server;
        Server (ServerSocket server) {
            super ();
            this.server = server;
        }
        void readAll (Socket s) throws IOException {
            byte[] buf = new byte [128];
            InputStream is = s.getInputStream ();
            s.setSoTimeout(1000);
            try {
                while (is.read(buf) > 0) ;
            } catch (SocketTimeoutException x) { }
        }
        /*
         * Our "http" server to return a 404
         */
        public void run() {
            try {
                Socket s = server.accept();
                readAll(s);

                PrintStream out = new PrintStream(
                                                  new BufferedOutputStream(
                                                                           s.getOutputStream() ));

                /* send the header */
                out.print("HTTP/1.1 200 OK\r\n");
                out.print("Content-Type: text/html; charset=iso-8859-1\r\n");
                out.print("Content-Length: 78\r\n");
                out.print("\r\n");
                out.print("<HTML>");
                out.print("<HEAD>File Content");
                out.print("<BODY>A dummy body.");
                out.print("</HTML>");
                out.flush();

                s.close();
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                try { server.close(); } catch (IOException unused) {}
            }
        }
    }


    public static void main(String args[]) throws Exception {
        ServerSocket ss = new ServerSocket(0);
        Server s = new Server (ss);
        s.start();

        String url = "http://127.0.0.1:"+ss.getLocalPort();

        // start fetch in its own thread group
        ThreadGroup grp = new ThreadGroup("MyGroup");

        // http request in another thread group
        Thread thr = new Thread(grp, new Fetcher(url));
        thr.start();
        thr.join();

        // fetcher is done - the group should now be empty
        if (grp.activeCount() > 0) {
            throw new RuntimeException("Keep-alive thread started in wrong thread group");
        }

        grp.destroy();
    }

}

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Java example source code file (KeepAliveTimerThread.java)

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The KeepAliveTimerThread.java Java example source code

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