shared_queue.java

public class AwesomeClass {
  // a concurrent queue shared with Node
  private final Queue<Object> queue;
  
  public AwesomeClass(Queue<Object> queue) {
    this.queue = queue;
  }
  
  public void start() {
    Thread thread = new Thread(new Runnable() {
      @Override
      public void run() {
        // simulate asynchronous events, e.g., an HTTP request or a long computation
        while (serverIsOnline) {
          Object data = doSomeComputation();
          // awake the Node.js worker, which will notify the main Node.js' loop
          queue.offer(data);
        }
      }
    });
    thread.start();
  }  
}