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Pure Java implementation of libzmq (

CircleCI Quality Gate Status Coverage Status Maven Central Javadocs


  • Based on libzmq 4.1.7.

  • ZMTP/3.0 (

  • tcp:// protocol and inproc:// is compatible with zeromq.

  • ipc:// protocol works only between jeromq (uses tcp:// internally).

  • Securities

  • Performance that's not too bad, compared to native libzmq.

  • Exactly same developer experience with zeromq and jzmq.

  • TCP KeepAlive Count, Idle and Interval are known to only work with JVM 13 and later.


  • ipc:// protocol with zeromq. Java doesn't support UNIX domain socket.

  • pgm:// protocol. Cannot find a pgm Java implementation.

  • norm:// protocol. Cannot find a Java implementation.

  • tipc:// protocol. Cannot find a Java implementation.

  • GSSAPI mechanism is not yet implemented.

  • Interrupting threads is still unsupported: library is NOT Thread.interrupt safe.


Contributions welcome! See for details about the contribution process and useful development tasks.



Add it to your Maven project's pom.xml:


    <!-- for the latest SNAPSHOT -->

    <!-- If you can't find the latest snapshot -->


To generate an ant build file from pom.xml, issue the following command:

mvn ant:ant

Getting started

Simple example

Here is how you might implement a server that prints the messages it receives and responds to them with "Hello, world!":

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

public class hwserver
    public static void main(String[] args) throws Exception
        try (ZContext context = new ZContext()) {
            // Socket to talk to clients
            ZMQ.Socket socket = context.createSocket(SocketType.REP);

            while (!Thread.currentThread().isInterrupted()) {
                // Block until a message is received
                byte[] reply = socket.recv(0);

                // Print the message
                    "Received: [" + new String(reply, ZMQ.CHARSET) + "]"

                // Send a response
                String response = "Hello, world!";
                socket.send(response.getBytes(ZMQ.CHARSET), 0);

More examples

The JeroMQ translations of the zguide examples are a good reference for recommended usage.


For API-level documentation, see the Javadocs.

This repo also has a doc folder, which contains assorted "how to do X" guides and other useful information about various topics related to using JeroMQ.


All source files are copyright © 2007-2022 contributors as noted in the AUTHORS file.

Free use of this software is granted under the terms of the Mozilla Public License 2.0. For details see the file LICENSE included with the JeroMQ distribution.