Socket frontend = ctx.createSocket(ZMQ.ROUTER);
Socket backend = ctx.createSocket(ZMQ.ROUTER);
frontend.setHWM (-1);
backend.setHWM (-1);
frontend.bind("tcp://*:5555");
backend.bind("tcp://*:5556");
while (!Thread.currentThread().isInterrupted()) {
ZMQ.Poller items = new ZMQ.Poller(2);
items.register(frontend, ZMQ.Poller.POLLIN);
items.register(backend, ZMQ.Poller.POLLIN);