Java Concurrency

Open-source Java projects categorized as Concurrency

Top 15 Java Concurrency Projects

  • Disruptor

    High Performance Inter-Thread Messaging Library

    Project mention: LMAX Disruptor – High Performance Inter-Thread Messaging Library | /r/hackernews | 2023-11-20
  • Vert.x

    Vert.x is a tool-kit for building reactive applications on the JVM

    Project mention: Reactive database access on the JVM | | 2023-07-13

    Hibernate Reactive integrates with Vert.x, but an extension allows to bridge to Project Reactor if wanted

  • InfluxDB

    Collect and Analyze Billions of Data Points in Real Time. Manage all types of time series data in a single, purpose-built database. Run at any scale in any environment in the cloud, on-premises, or at the edge.

  • Android-RxJava

    Learning RxJava for Android by example

  • Quasar

    Fibers, Channels and Actors for the JVM (by puniverse)

    Project mention: Java 21 makes me like Java again | | 2023-09-16

    Java 21 doesn't retrofit green threads though. Quasar [0] is a library that implemented fibers for Java and the main developer pron has joined the OpenJDK development team. All that was necessary for first party support is to make the JDK libraries yield when blocking.

    Adopting async isn't impossible at all, there is very little demand for it.


  • JCTools

  • Apache Log4j 2

    Apache Log4j 2 is a versatile, feature-rich, efficient logging API and backend for Java.

    Project mention: Log4j requesting feedback on which modules/features to drop | | 2023-09-28
  • ea-async

    EA Async implements async-await methods in the JVM.

    Project mention: Fluent: Static Extension Methods for Java | | 2023-07-02

    I feel like this misses the reason I like extension methods: discoverability.

    With an extension method, I can do `object.` and my IDE will tell me what can be called on object. With a static helper method, it isn't as easy to know what is available. I need to know which helpers actually exist.

    Since this doesn't have IDE support, it doesn't help discoverability. I'm not going to get nice autocomplete that shows me what is available. In fact, my IDE is going to highlight it as a bug. If I have a spelling mistake, I won't be able to easily pick it up - I'll assume it's just the normal complaint for all of these fluent extension methods.

    That makes this simply syntactic sugar rather than something that actually helps me discover things more easily. It then hurts readability and navigation since I can't easily click through to get the definition of the method.

    On a more general note about Java, things like this are one of the reasons I don't love the Java ecosystem. People try to change the behavior of Java in really hacky ways that don't work well. I understand that it's an attempt to overcome shortcomings in the language, but when one looks other languages it becomes clear that Java could have just evolved the language to be better. Java has lots of good things and I'm not looking to argue that. However, when I look at things like this, it makes me think that Java needs to really address the core language.

    Instead, we get lots of tools like this which might be nice, but make it really hard to understand what's going on. Electronic Arts created an async/await library that'll do crazy stuff to let you do async/await style programming ( Yes, Java is doing good things with structured concurrency and Project Loom, but the point is how people keep trying to work around the language. There are so many POJO generators it isn't funny: AutoValue, Immutables, JodaBeans, Lombok, and more I'm probably forgetting. Java records don't fulfill everything (and they're at least a decade late). Java doesn't support expression trees for lambdas so libraries sometimes do crazy hacky things to make that exist.

    Java is a great piece of technology, but it feels like people are often trying to overcome issues with the language through really hacky means in a way that I don't see in other languages. Java is getting better about modernizing the language, but it still feels like people are running against the language more than in other ecosystems.

  • Onboard AI

    Learn any GitHub repo in 59 seconds. Onboard AI learns any GitHub repo in minutes and lets you chat with it to locate functionality, understand different parts, and generate new code. Use it for free at

  • react-native-threads

    Create new JS processes for CPU intensive work

  • java-concurrency-examples

    Java Concurrency/Multithreading Tutorial with Examples for Dummies

  • lingua-franca

    Intuitive concurrent programming in any language

  • Composer

    Library for composability of interdependent non-blocking I/O tasks (by krupalshah)

  • money-transfer-rest-api

    Simple implementation of RESTful API for money transfers between accounts

  • time-series-concurrency-example

    Time Series Data and CompletableFuture example in Java

  • ExcelPasswordCracker

    A simple brute-force attack password cracker for Excel files with multi-threaded implementation.

    Project mention: Sacked employee with password protected excel files | /r/msp | 2023-03-11
  • Concurrent-Checkers-Game

    Concurrent/simultaneous checkers game for up to 8 players. Built this in correspondence to but to play Checkers as there is no such game that exists on the WWW.

  • SaaSHub

    SaaSHub - Software Alternatives and Reviews. SaaSHub helps you find the best software and product alternatives

NOTE: The open source projects on this list are ordered by number of github stars. The number of mentions indicates repo mentiontions in the last 12 Months or since we started tracking (Dec 2020). The latest post mention was on 2023-11-20.

Java Concurrency related posts


What are some of the best open-source Concurrency projects in Java? This list will help you:

Project Stars
1 Disruptor 16,641
2 Vert.x 13,863
3 Android-RxJava 7,559
4 Quasar 4,538
5 JCTools 3,400
6 Apache Log4j 2 3,206
7 ea-async 1,342
8 react-native-threads 714
9 java-concurrency-examples 253
10 lingua-franca 190
11 Composer 19
12 money-transfer-rest-api 14
13 time-series-concurrency-example 6
14 ExcelPasswordCracker 5
15 Concurrent-Checkers-Game 4
SaaSHub - Software Alternatives and Reviews
SaaSHub helps you find the best software and product alternatives