"\ndebug    = " + debug +
    public static void main(String[] args) {        MulticastSocket sock=null;        Receiver receiver=null;        int num_msgs=1000;        byte[] buf;        DatagramPacket packet;        InetAddress group_addr=null;        int[][] matrix;        boolean jg=false; // use JGroups channel instead of UDP MulticastSocket        JChannel channel=null;        String props=null, loopback_props;        String group_name="SpeedTest-Group";        Message send_msg;        boolean debug=false;        Debugger debugger=null;        long sleep_time=1; // sleep in msecs between msg sends        boolean busy_sleep=false;        boolean yield=false;        int num_yields=0;        boolean loopback=false;        props="UDP(mcast_addr=224.0.0.36;mcast_port=55566;ip_ttl=32;" +                "ucast_send_buf_size=32000;ucast_recv_buf_size=64000;" +                "mcast_send_buf_size=32000;mcast_recv_buf_size=64000):" +                "PING(timeout=2000;num_initial_members=3):" +                "MERGE2(min_interval=5000;max_interval=10000):" +                "FD_SOCK:" +                "VERIFY_SUSPECT(timeout=1500):" +                "pbcast.NAKACK(max_xmit_size=8192;gc_lag=50;retransmit_timeout=600,800,1200,2400,4800):" +                "UNICAST(timeout=1200):" +                "pbcast.STABLE(desired_avg_gossip=10000):" +                "FRAG(frag_size=8192;down_thread=false;up_thread=false):" +// "PIGGYBACK(max_size=16000;max_wait_time=500):" +                "pbcast.GMS(join_timeout=5000;join_retry_timeout=2000;" +                "shun=false;print_local_addr=true):" +                "pbcast.STATE_TRANSFER";        // "PERF(details=true)";        loopback_props="LOOPBACK:" +                "PING(timeout=2000;num_initial_members=3):" +                "MERGE2(min_interval=5000;max_interval=10000):" +                "FD_SOCK:" +                "VERIFY_SUSPECT(timeout=1500):" +                "pbcast.NAKACK(gc_lag=50;retransmit_timeout=600,800,1200,2400,4800):" +                "UNICAST(timeout=5000):" +                "pbcast.STABLE(desired_avg_gossip=20000):" +                "FRAG(frag_size=16000;down_thread=false;up_thread=false):" +                "pbcast.GMS(join_timeout=5000;join_retry_timeout=2000;" +                "shun=false;print_local_addr=true):" +                "pbcast.STATE_TRANSFER";        for(int i=0; i < args.length; i++) {            if("-help".equals(args[i])) {                help();                return;            }            if("-jg".equals(args[i])) {                jg=true;                continue;            }            if("-loopback".equals(args[i])) {                loopback=true;                props=loopback_props;                continue;            }            if("-props".equals(args[i])) {                props=args[++i];                continue;            }            if("-debug".equals(args[i])) {                debug=true;                continue;            }            if("-busy_sleep".equals(args[i])) {                busy_sleep=true;                continue;            }            if("-yield".equals(args[i])) {                yield=true;                num_yields++;                continue;            }            if("-sleep".equals(args[i])) {                sleep_time=Long.parseLong(args[++i]);                continue;            }            if("-num_msgs".equals(args[i])) {                num_msgs=Integer.parseInt(args[++i]);                continue;            }            help();            return;        }        System.out.println("jg       = " + jg +                "\nloopback = " + loopback +                "\ndebug    = " + debug +                "\nsleep    = " + sleep_time +                "\nbusy_sleep=" + busy_sleep +                "\nyield=" + yield +                "\nnum_yields=" + num_yields +                "\nnum_msgs = " + num_msgs +                           '\n');        try {            matrix=new int[num_msgs][2];            for(int i=0; i < num_msgs; i++) {                for(int j=0; j < matrix[i].length; j++)                    matrix[i][j]=0;            }            if(jg) {                channel=new JChannel(props);                channel.connect(group_name);                if(debug) {                    debugger=new Debugger(channel);                    debugger.start();                }            }            else {                group_addr=InetAddress.getByName("224.0.0.36");                sock=new MulticastSocket(7777);                sock.joinGroup(group_addr);            }            if(debug) {                System.out.println("Press key to start");                System.in.read();            }            receiver=new Receiver(sock, channel, matrix, jg);            receiver.start();            ByteBuffer bb=ByteBuffer.allocate(16);            bb.mark();            start=System.currentTimeMillis();            for(int i=0; i < num_msgs; i++) {                bb.reset();                bb.putInt(i);                buf=(byte[])(bb.array()).clone();                if(jg) {                    send_msg=new Message(null, null, buf);                    channel.send(send_msg);                }                else {                    packet=new DatagramPacket(buf, buf.length, group_addr, 7777);                    sock.send(packet);                }                if(i % 1000 == 0)                    System.out.println("-- sent " + i);                matrix[i][0]=1;                if(yield) {                    for(int k=0; k < num_yields; k++) {                        Thread.yield();                    }                }                else {                    if(sleep_time > 0) {                        sleep(sleep_time, busy_sleep);                    }                }            }            while(true) {                System.in.read();                printMatrix(matrix);            }        }        catch(Exception ex) {            System.err.println(ex);        }    }