Awesome JVM

Jitescript - Java API for Bytecode

A constant throughput, correct latency recording variant of wrk

Frege is a Haskell for the JVM. It brings purely functional programing to the Java platform.

GoJava - Java bindings for Go packages

JPHP - an implementation of PHP on Java VM

Rembulan, an implementation of Lua 5.3 for the Java Virtual Machine

Statistical Machine Intelligence & Learning Engine

Reactive Programming for Android

High Performance data structures and utility methods for Java

Bloofi: A java implementation of multidimensional Bloom filters

A high performance caching library for Java

Chronicle Bytes has a similar purpose to Java NIO's ByteBuffer with many extensions

Micro second messaging that stores everything to disk

Replicate your Key Value Store across your network, with consistency, persistance and performance.

Clojure's data structures modified for use outside of Clojure

binary serialization format

High performance Java implementation of a Cuckoo filter - Apache Licensed

An advanced, but easy to use, platform for writing functional applications in Java 8.

Eclipse Collections is a collections framework for Java with optimized data structures and a rich, functional and fluent API.

External-Memory Sorting in Java

Fault tolerance and resilience patterns for the JVM

A Java library for quickly and efficiently parsing and writing UUIDs

Geohash utitlies in java

GS Collections has been migrated to the Eclipse Foundation, re-branded as Eclipse Collections. https://www.eclipse.org/collections/

Hollow is a java library and toolset for disseminating in-memory datasets from a single producer to many consumers for high performance read-only access.

A fork of Cliff Click's High Scale Library. Improved with bug fixes and a real build system.

High Performance Primitive Collections for Java

Java port of a concurrent trie hash map implementation from the Scala collections library

Java library for the HyperLogLog algorithm

A simple integer compression library in Java

Implementation of various string similarity and distance algorithms: Levenshtein, Jaro-winkler, n-Gram, Q-Gram, Jaccard index, Longest Common Subsequence edit distance, cosine similarity ...

jOOλ - The Missing Parts in Java 8 jOOλ improves the JDK libraries in areas where the Expert Group's focus was elsewhere. It adds tuple support, function support, and a lot of additional functionality around sequential Streams. The JDK 8's main efforts (default methods, lambdas, and the Stream API) were focused around maintaining backwards compatibility and implementing a functional API for parallelism.

Java Collections till the last breadcrumb of memory and performance

Port of LevelDB to Java

A very memory-efficient trie (radix tree) implementation

LMDB for Java

Lightning Memory Database (LMDB) for Java: a low latency, transactional, sorted, embedded, key-value store

Library for creating In-memory circular buffers that use direct ByteBuffers to minimize GC overhead

LWJGL is a Java library that enables cross-platform access to popular native APIs useful in the development of graphics (OpenGL, Vulkan), audio (OpenAL), parallel computing (OpenCL, CUDA) and XR (OpenVR, LibOVR) applications.

Immutable key/value store with efficient space utilization and fast reads. They are ideal for the use-case of tables built by batch processes and shipped to multiple servers.

Java large off heap cache

A modern I/O library for Android, Java, and Kotlin Multiplatform.

The Java API for Onyx

A java.util.HashMap compatible map that won't stall puts or gets when resizing

A Persistent Java Collections Library

Immutable in-memory R-tree and R*-tree implementations in Java with reactive api

RTree2D is a 2D immutable R-tree for ultra-fast nearest and intersection queries in plane and spherical coordinates

A better compressed bitset in Java

Rolling hash functions in Java

RxJava – Reactive Extensions for the JVM – a library for composing asynchronous and event-based programs using observable sequences for the Java VM.

A gulp of low latency Java

Simple Binary Encoding (SBE) - High Performance Message Codec

Parallel boolean circuit evaluation

A fast object pool for the JVM

Stream summarizer and cardinality estimator.

Fast integer compression in C using the StreamVByte codec

A Java implementation of Transducers

a fast, scalable, multi-language and extensible build system

gRPC and protocol buffers for Android, Kotlin, and Java.

Zero-allocation hashing for Java

A collection of source code generators for Java.

Testing tools for javac and annotation processors

Java 8 annotation processor and framework for deriving algebraic data types constructors, pattern-matching, folds, optics and typeclasses.

Catch common Java mistakes as compile-time errors

The Eta Programming Language, a dialect of Haskell on the JVM

Write parsers for arbitrary text inputs, entirely in Java, with no preprocessing phase

Java 1-15 Parser and Abstract Syntax Tree for Java, including preview features to Java 13

A Java API for generating .java source files.

Build parsers in Java

Elegant parsing in Java and Scala - lightweight, easy-to-use, powerful.

Obsolete repository. Moved to oracle/graal.

Compiler of Java bytecode to JavaScript

GraalVM: Run Programs Faster Anywhere

A JNI code generator based on the JNI generator used by the eclipse SWT project

Compile Java byte-code to native CPU's.

Java Bindings for V8

The missing bridge between Java and native C++

Java Abstracted Foreign Function Layer

Jssembly is a library that allows you to execute native assembly from Java.

Low-overhead, non-blocking I/O, external Process implementation for Java

Efficient reliable UDP unicast, UDP multicast, and IPC message transport

Your go-to microservice framework for any situation, from the creator of Netty et al. You can build any type of microservice leveraging your favorite technologies, including gRPC, Thrift, Kotlin, Retrofit, Reactive Streams, Spring Boot and Dropwizard.

A High Performance Network ( TCP/IP ) Library

Simulating shitty network connections so you can build better systems.

GoReplay is an open-source tool for capturing and replaying live HTTP traffic into a test environment in order to continuously test your system with real data. It can be used to increase confidence in code deployments, configuration changes and infrastructure changes.

jRT measures the response time of a java application to socket-based requests

Java API over Accelio

"I am fluent in over 6 million forms of communication!"

Chaos engineering tool for simulating real-world distributed system failures

Square’s meticulous HTTP client for the JVM, Android, and GraalVM.

Unconventional I/O library for Java

Proteus Java Client

Reactive stubs for gRPC

Tools for keeping your cloud operating in top form. Chaos Monkey is a resiliency tool that helps applications tolerate random instance failures.

A Java library for capturing, crafting, and sending packets.

A Linux packet crafting tool.

TCP/IP packet demultiplexer. Download from:

Pcap editing and replay tools for *NIX and Windows - Users please download source from

BCC - Tools for BPF-based Linux IO analysis, networking, monitoring, and more

simple disk I/0 latency measuring tool

Performance monitoring and benchmarking suite

Performance analysis tools based on Linux perf_events (aka perf) and ftrace

A Java agent that rewrites bytecode to instrument allocation sites

Java memory allocation profiler

Sampling CPU and HEAP profiler for Java featuring AsyncGetCallTrace + perf_events

BTrace - a safe, dynamic tracing tool for the Java platform

Turn -XX:+TraceBytecodes output into a FlameGraph compatible stack format

Fork of tagtraum industries' GCViewer. Tagtraum stopped development in 2008, I aim to improve support for Sun's / Oracle's java 1.6+ garbage collector logs (including G1 collector)

Performance visualisation tools

Utilities for HDR Histogram logs manipulation

production heap profiling for the JVM. compatible with google-perftools.

A sampling JVM profiler without the safepoint sample bias

Java Agent for Memory Measurements

Memory consumption estimator for Java

Get Method Sampling from Java Flight Recorder Dump and convert to FlameGraph compatible format.

Tool for creating reports from Java Flight Recorder dumps

Log analyser / visualiser for Java HotSpot JIT compiler. Inspect inlining decisions, hot methods, bytecode, and assembly. View results in the JavaFX user interface.

JITWatch plugin for IntelliJ IDEA

GUI for comparing JMH results

Java monitoring for the command-line, profiler included

JVM Profiler Sending Metrics to Kafka, Console Output or Custom Reporter

A memory leak detection library for Android.

An application metrics facade for the most popular monitoring tools. Think SLF4J, but for metrics.

A java agent to generate method mappings to use with the linux perf tool

PerfJ is a wrapper of linux perf for java programs.

OOM diagnostics for Java.

Sends stacktrace-level performance data from a JVM process to Riemann.

Simple JVM Profiler Using StatsD and Other Metrics Backends

Small set of tools for JVM troublshooting, monitoring and profiling.

Best-of-breed OpenTracing utilities, instrumentations and extensions

Zipkin is a distributed tracing system

Dead-Simple Packaging and Deployment for JVM Apps

Fast JVM launching without the hassle of persistent JVMs.

Java unlimited redefinition of classes at runtime.

Terminate the JVM when resources are exhausted

[INACTIVE] Avian is a lightweight virtual machine and class library designed to provide a useful subset of Java's features, suitable for building self-contained applications.

Eclipse OpenJ9: A Java Virtual Machine for OpenJDK that's optimized for small footprint, fast start-up, and high throughput. Builds on Eclipse OMR (https://github.com/eclipse/omr) and combines with the Extensions for OpenJDK for OpenJ9 repo.

A Java to iOS Objective-C translation tool and runtime.

A toy JVM written in Go

Cross-platform framework for building truly native mobile apps with Java or Kotlin. Write Once Run Anywhere support for iOS, Android, Desktop & Web.

Ahead of time compiler for JVM bytecode targetting iOS, Mac OSX and Linux

Examples and hands-on labs for Linux tracing tools workshops

Class materials for a distributed systems lecture series