Multithreaded relay in Java

package guide;

import org.zeromq.SocketType;
import org.zeromq.ZContext;
import org.zeromq.ZMQ.Socket;

/**
* Multithreaded relay
*/

public class mtrelay
{

private static class Step1 extends Thread
{
private ZContext context;

private Step1(ZContext context)
{
this.context = context;
}

@Override
public void run()
{
// Signal downstream to step 2
Socket xmitter = context.createSocket(SocketType.PAIR);
xmitter.connect("inproc://step2");
System.out.println("Step 1 ready, signaling step 2");
xmitter.send("READY", 0);
xmitter.close();
}

}

private static class Step2 extends Thread
{
private ZContext context;

private Step2(ZContext context)
{
this.context = context;
}

@Override
public void run()
{
// Bind to inproc: endpoint, then start upstream thread
Socket receiver = context.createSocket(SocketType.PAIR);
receiver.bind("inproc://step2");

// Wait for signal
receiver.recv(0);
receiver.close();

// Connect to step3 and tell it we're ready
Socket xmitter = context.createSocket(SocketType.PAIR);
xmitter.connect("inproc://step3");
System.out.println("Step 2 ready, signaling step 3");
xmitter.send("READY", 0);
xmitter.close();
}

}

private static class Step3 extends Thread
{
private ZContext context;

private Step3(ZContext context)
{
this.context = context;
}

@Override
public void run()
{
// Bind to inproc: endpoint, then start upstream thread
Socket receiver = context.createSocket(SocketType.PAIR);
receiver.bind("inproc://step3");

// Wait for signal
receiver.recv(0);
receiver.close();

System.out.println("Step 3 ready");
}

}

public static void main(String[] args) throws InterruptedException
{
try (ZContext context = new ZContext()) {
// Step 1 signals to step 2
Thread step1 = new Step1(context);
step1.start();

// Step 2 relays the signal from step 1 to step 3
Thread step2 = new Step2(context);
step2.start();

// Step 3 waits for signal from step 2
Thread step3 = new Step3(context);
step3.start();

step1.join();
step2.join();
step3.join();

System.out.println("Test successful!");
}
}
}