Tools for bytecode manipulation and analysis.
- asmtools - Used to develop tools for the production of Java .class files.
- Byte Buddy - Code generation library creating Java classes at runtime without the help of a compiler.
- Jitescript - Bytecode generation library similar to BiteScript.
Garbage collectors for the JVM.
- Azul Pauseless Garbage Collection - Providing continuous, pauseless operation for Java applications.
- Balanced GC - GC policy available in the Java Virtual Machine for IBM WebSphere Application Server V8.
- Epsilon GC - Completely passive GC implementation with bounded allocation limit, and lowest runtime performance overhead possible.
- G1 - The Garbage-First Garbage Collector.
- Shenandoah - Ultra-Low-Pause-Time Garbage Collector.
- The Garbage Collection Handbook - Book that addresses new challenges to garbage collection made by recent advances in hardware and software.
- ZGC - Garbage collector optimized for low latency and very large heaps.
Tools that generate load and measure the system accurately without coordinated omission
- Gatling - Asynchronous non-blocking scenario driven load testing tool for testing HTTP servers.
- wrk2 - A constant throughput, correct latency recording variant of wrk.
Languages running on the JVM.
- Ceylon - Object-oriented, strong and static programming language with an emphasis on immutability, created by Red Hat.
- Clojure - Dialect of Lisp created by Rich Hickey. Dynamically typed with emphasis on functional programming.
- Erjang - A JVM-based Erlang VM.
- Eta - Pure, lazy, strongly typed functional programming language on the JVM.
- Frege - Pure functional programming language in the spirit of Haskell.
- gojava - Java bindings for Go packages.
- Golo - A simple dynamic language that makes extensive usage of
- Groovy - Optionally typed and dynamic language, with static-typing and static compilation capabilities.
- Java - General-purpose, concurrent, strongly typed, class-based object-oriented language.
- JRuby - Implementation of the Ruby language on the JVM.
- JPHP - PHP on the Java VM.
- Jython - Python for the Java Platform.
- Kawa - Extension of the Scheme language, which is in the Lisp family of programming languages.
- Kotlin - Statically typed programming language for the JVM, Android and the browser.
- LuaJ - Java-centric implementation of lua vm built to leverage standard Java features.
- OCaml-Java - Supports OCaml language v4. Generates plain Java bytecode and have seamless integration with Java.
- Rembulan - Rembulan is an implementation of Lua 5.3 for the JVM, written in pure Java with minimal dependencies.
- Renjin - JVM-based interpreter for the R language for the statistical analysis
- Scala - Strong and static programming language that combine object-oriented and functional programming ideas.
- Xtend - Flexible and expressive dialect of Java, which compiles into Java 5 source code.
- Deeplearning4j - Open-Source, Distributed, Deep Learning Library for the JVM.
- H2O - Fast statistical, machine learning & math runtime.
- Smile - Statistical Machine Intelligence & Learning Engine.
Memory and concurrency
Tools and data structures for efficient memory layout and concurrent access.
- Agera - Reactive Programming for Android by Google.
- Agrona - Library of data structures and utility methods that are a common need when building high-performance applications.
- Apache Arrow - A high-performance cross-system data layer for columnar in-memory analytics.
- bloofi - Java implementation of multidimensional Bloom filters
- Cap’n Proto - Insanely fast data interchange format and capability-based RPC system.
- caffeine - A high performance caching library for Java 8.
- Chronicle-Bytes - Low level memory access wrappers.
- Chronicle-Queue - Micro second messaging that stores everything to disk.
- Chronicle-Map - In-memory key-value store designed for low-latency and/or multi-process applications.
- clj-ds - Clojure's data structures modified for use outside of Clojure.
- colfer - Binary serialization format and class generator.
- commons-math - Library of lightweight, self-contained mathematics and statistics components.
- CuckooFilter4J - Bloom filter replacement for approximated set-membership queries.
- cyclops - Integration modules for RxJava, Reactor, FunctionalJava, Guava & Javaslang.
- Eclipse Collections - Collections framework for Java.
- externalsortinginjava - Sort very large files using multiple cores and an external-memory algorithm.
- failsafe - A lightweight, zero-dependency library for handling failures.
- fasttuple - Collections that are laid out adjacently in both on- and off-heap memory.
- fast-uuid - Java library for quickly and efficiently parsing and writing UUIDs.
- geohash - Java utility methods for geohashing.
- gs-collections - Goldman Sachs collections framework.
- hollow - Java library and comprehensive toolset for harnessing small to moderately sized in-memory datasets.
- high-scale-lib - Cliff Click's High Scale Library.
- hppc - High Performance Primitive Collections.
- injector - A new Executor for Java.
- java-concurrent-hash-trie-map - Java port of a concurrent trie hash map implementation from Scala collections.
- java-hll - Java library for the HyperLogLog algorithm.
- JavaFastPFOR - Library to compress and uncompress arrays of integers very fast.
- java-string-similarity - String similarity and distance measures, including Levenshtein edit distance and sibblings, Jaro-Winkler, Longest Common Subsequence, cosine similarity etc.
- JCTools - Concurrent data structures currently missing from the JDK.
- DSL-JSON - High performance JSON library with advanced compile-time databinding.
- jsoniter - Claims to be the fastest JSON parser ever (copy of DSL-JSON).
- jOOL - Useful extensions to Java 8 lambdas.
- Koloboke - Java Collections til the last breadcrumb of memory and performance.
- LevelDB - Rewrite (port) of LevelDB in Java.
- lightweight_trie - A very memory-efficient trie (radix tree) implementation.
- lmdbjni - Java API to LMDB (HawtJNI) which is an ultra-fast, ultra-compact key-value embedded data store written in C.
- lmdbjava - Java API to LMDB (JNR) which is an ultra-fast, ultra-compact key-value embedded data store written in C.
- low-gc-membuffers - In-memory circular buffers that use direct ByteBuffers to minimize GC overhead.
- lwjgl3 - Java library that enables cross-platform access to popular native APIs useful in the development of graphics (OpenGL), audio (OpenAL) and parallel computing (OpenCL) applications.
- MapDB - Collections backed by off-heap or on-disk storage.
- mph-table - Minimal Perfect Hash Tables are an immutable key/value store with efficient space utilization and fast reads.
- mug - A small, zero-dep functional util library originating from Google.
- netty-buffers - Memory buffer pool implementation similar to jemalloc.
- ObjectLayout - A layout-optimized Java data structure package.
- ohc - Java large off heap cache developed for Apache Cassandra 3.0.
- okio - Modern Java IO library that do clever things to save CPU and memory.
- onyx-java - Mirrors the Onyx Platform core API by providing a Java equivalent for each component of an Onyx workflow.
- parquet - Columnar storage format that uses the record shredding and assembly algorithm described in the Dremel paper.
- PauselessHashMap - A java.util.HashMap compatible map that won't stall puts or gets when resizing.
- pcollections - A Persistent Java Collections Library.
- protobuf - Google's data interchange format.
- Quasar - Lightweight threads and actors for the JVM.
- rtree - Immutable in-memory R-tree and R*-tree implementations in Java with reactive api.
- RTree2D - RTree2D is a 2D immutable R-tree with STR (Sort-Tile-Recursive) packing for ultra-fast nearest and intersection queries on plane and spherical surfaces.
- Reactive Streams - Standard for asynchronous stream processing with non-blocking back pressure.
- Reactive Streams Utilities - Future standard utilities library for Reactive Streams.
- RoaringBitmap - A better compressed bitset in Java.
- rollinghashjava - Rolling hash functions in Java.
- Reactor - Reactive data applications on the JVM for Java, Groovy, Clojure and other.
- RxJava - Library for composing asynchronous and event-based programs using observable sequences.
- SmoothieMap - java.util.Map impl with worst put latencies more than 100 times smaller than java.util.HashMap.
- Simple Binary Encoding - High Performance Message Codec.
- splitmap - A parallel bitmap implementation.
- DataSketches - A Java software library of stochastic streaming algorithms.
- stormpot - A fast object pool for the JVM.
- stream-lib - A Java library for summarizing data in streams for which it is infeasible to store all events.
- streamvbyte - Fast integer compression in C using the StreamVByte codec.
- TraneIO - High-performance implementation of the Future abstraction.
- transducers-java - Composable algorithmic transformations independent from the context of their input and output sources.
- VarInt - No-deps variable int implementation without deps (by Bazel).
- vavr - Functional Library for Java 8+.
- wire - Clean, lightweight protocol buffers for Android and Java.
- Zero-Allocation-Hashing - Hashing any sequences of bytes in Java, including all kinds of primitive arrays, buffers, CharSequences and more.
Parsers, interpreters, compilers and source generation targeted for the JVM.
- Antlr - Parser generator for reading, processing, executing, or translating structured text or binary files.
- auto - A collection of source code generators for Java.
- Apache Calcite - Dynamic data management framework and SQL parser plugin.
- Checker Framework - Compiler plug-ins that find bugs or verify their absence.
- compile-testing - Testing tools for javac and annotation processors.
- derive4j - Algebraic data types constructors, pattern-matching, morphisms, optics and typeclasses.
- error-prone - Catch common Java mistakes as compile-time errors.
- GHCVM - A Haskell to JVM compiler that supports GHC Haskell.
- Graal - New experimental just-in-time compiler for Java that is integrated with the HotSpot virtual machine.
- grappa - Java fork of Parboiled. Write grammars with no preprocessing phase.
- immutables - Generate simple, safe and consistent value objects.
- javacc - Parser generator for use with Java.
- javaparser - Java 1.8 Parser and Abstract Syntax Tree for Java.
- JavaPoet - A Java API for generating .java source files.
- jparsec - Builds mini parsers in pure Java a la Haskell Parsec.
- MPS - Design and build extensible DSLs and editors.
- lombok - Reduce the amount of boilerplate code that is commonly written for Java classes.
- parboiled - Parsing of arbitrary input text based on parsing expression grammars.
- Sulong - LLVM IR interpreter written in Java using Truffle and Graal.
- Truffle - Framework for implementing languages as simple interpreters.
- Xtext - Framework for development of programming languages and DSLs.
Interconnecting JVM and native code
- hawtjni - A JNI code generator based on the JNI generator used in Eclipse SWT.
- Java Grinder - Compile Java bytecode to microcontroller assembly.
- JavaCPP - JavaCPP provides efficient access to native C++ inside Java.
- jnr-ffi - Load native libraries without writing JNI code by hand.
- jssembly - Execution of native assembly from Java.
- NuProcess - A low-overhead, non-blocking I/O, external Process execution implementation for Java.
- Project Panama - Enriching the connections between the JVM and APIs used by C programmers.
Tools for network programming, packet capture, monitoring, testing and resiliency.
- Aeron - Efficient reliable UDP unicast, UDP multicast, and IPC message transport.
- armeria - Asynchronous RPC/API client/server library built on top of Java 8, Netty 4.1, HTTP/2, and Thrift.
- Chronicle-Network - A High Performance Network library.
- comcast - Simulating shitty network connections.
- gor - HTTP traffic replay in real-time.
- gRPC - A high performance, open source, general RPC framework that puts mobile and HTTP/2 first.
- jRT - Measures response time of a java application to socket-based requests.
- JXIO - Java API over AccelIO (C library), a high-performance asynchronous reliable messaging and RPC library optimized for hardware acceleration.
- K3PO - Create arbitrary network traffic and behavior to certify whether a network endpoint behaves correctly.
- muxy - Simulating real-world distributed system failures.
- Netty - Async event-driven network library for high performance protocol servers & clients.
- okhttp - An HTTP+HTTP/2 client for Android and Java applications.
- one-nio - library for building high performance Java servers.
- proteus-java - Proteus Java Client based on RSocket.
- reactive-grpc - Reactive gRPC is a suite of libraries for using gRPC with Reactive Streams programming libraries.
- RSocket - RSocket is a binary protocol for use on byte stream transports such as TCP, WebSockets, and Aeron.
- SimianArmy - Resiliency tool that helps ensure that your applications can tolerate random instance failures.
- pcap4j - Java library for capturing, crafting, and sending packets using libpcap.
- pig - A Linux packet crafting tool.
- tcpdump - Packet analyzer for network traffic capture.
- tcpflow - Captures TCP connections flows in a way that is convenient for protocol analysis and debugging.
- tcpreplay - Pcap editing and replay tools.
Useful *nix tools when profiling the JVM and interaction with the host environment
- atoptool - Logging of system and process activity for long-term analysis, highlighting overloaded system.
- bcc - Tools for BPF-based Linux IO analysis, networking, monitoring, and more.
- Flame Graphs - Visualization of profiled software, allowing the most frequent code-paths to be identified quickly and accurately.
- ioping - Simple disk I/0 latency measuring tool.
- javap - Disassembles class files into code that reflects the java bytecode.
- jhat - Java Heap Analysis Tool
- jhsdb - Launch a postmortem debugger to analyze the content of a core-dump from a crashed JVM.
- jinfo - Prints configuration information for a given process.
- jstack - Prints stack traces of threads for a given Java process.
- jstat - Monitors GC and compiler statistics in the JVM.
- hwloc - Reports the structure of the processor, number of cores, hyperthreads and cache size.
- likwid - Read hardware performance counters on Intel and AMD processors.
- numactl - Control NUMA policy for processes or shared memory.
- oprofile - System-wide hardware performance monitoring with easy-to-use interface at low overhead.
- perf - Linux profiling with performance counters.
- perf-tools - Performance analysis tools based on Linux perf_events (aka perf) and ftrace.
- sysdig - Capture system state and activity from a running Linux instance, then save, filter and analyze.
- sysstat - Performance monitoring tools for Linux.
- taskset/process-affinity - Retrieve or set a processes’s CPU affinity.
- tiptop - Like top but also shows instructions per cycle (IPC).
Tools that provide profiling and tracing information to aid program optimization
- allocation-instrumenter - Java agent that rewrites bytecode to instrument allocation sites.
- aprof - Java memory allocation profiler.
- async-profiler - Sampling CPU profiler for Java featuring AsyncGetCallTrace + perf_events.
- BTrace - a safe, dynamic tracing tool for the Java platform.
- Byteman - tracing, monitoring and testing tool for Java
- bytestacks - Turn JVM bytecode execution into flame graphs.
- Chronon - Record your entire java program. Replay on any machine.
- GCeasy - Machine learning guided Garbage collection log analysis tool. Auto-detect problems in the JVM GC logs and recommend solutions to it.
- GCViewer - GCViewer is a tool that visualizes verbose GC output.
- grav - A collection of tools to help visualise process execution.
- hawkshaw - Tools for tracking down memory / JVM problems & generating predictable-as-possible VM behaviour.
- HdrHistogram - A Histogram that supports recording and analyzing sampled data value counts.
- hdrhistogram-metrics-reservoir - A Metrics Reservoir implementation backed by HdrHistogram.
- HdrLogProcessing - Utilities for HDR Histogram logs manipulation.
- heapster - Production heap profiling for the JVM.
- honest-profiler - Sampling JVM profiler without the safepoint sample bias.
- jamm - Measure actual object memory use including JVM overhead.
- Java Flight Recorder (JFR) - Tool for collecting diagnostic and profiling data about a running Java application with almost no performance overhead.
- java-sizeof - Memory consumption estimator for Java.
- jcstress - Experimental harness and tests to aid the research in the correctness of concurrency support in the JVM, class libraries, and hardware.
- jfr-flame-graph - Converting JFR Method Profiling Samples to FlameGraph compatible format.
- jfr-report-tool - Tool for creating reports from Java Flight Recorder dumps.
- jitwatch - Log analyser / visualiser for Java HotSpot JIT compiler.
- jitwatch-intellij - JITWatch plugin for IntelliJ IDEA.
- jHiccup - jHiccup is an open source tool designed to measure the pauses and stalls associated with an application’s underlying Java runtime platform.
- jmh - Micro benchmarks written in Java and other languages targetting the JVM.
- jmh-compare-gui - GUI for comparing JMH results.
- JOL - Analyze actual object layout schemes, footprint, and references in JVMs.
- JProfiler - Helps resolve performance bottlenecks, pin down memory leaks and understand threading issues.
- JVMTI - Provide a native API to inspect the state and to control the execution of applications running in the JVM.
- jvmtop - Lightweight console application to monitor running jvms on a machine in top-like manner.
- jvm-profiler - Java Agent to collect various metrics and stacktraces for Hadoop/Spark JVM processes in a distributed way.
- MAT - Java heap analyzer that help find memory leaks and reduce memory consumption.
- leakcanary - A memory leak detection library for Android and Java.
- metrics - Measure the behavior of critical components in production environment.
- micrometer - An application metrics facade for the most popular monitoring tools.
- osquery - osquery is an instrumentation framework that expose the operating system as a high-performance relational database.
- Overseer - Low-Level Hardware Monitoring and Management for Java.
- OpenTracing - A vendor-neutral open standard for distributed tracing.
- perf-map-agent - Generate method mappings to use with the linux
- perfj - Linux perf for java programs.
- polarbear - A tool to help diagnose OutOfMemoryError conditions.
- Riemann JVM Profiler - JVM agent which sends function-level profiler telemetry to a Riemann server for analysis, visualization, and storage.
- statsd-jvm-profiler - JVM agent profiler that sends profiling data to StatsD.
- Swiss Java Knife - Small set of tools for JVM troublshooting, monitoring and profiling.
- Takipi - Tells you when and why code breaks in production.
- Tracer - Manages custom trace identifiers and carries them through distributed systems.
- YourKit - Fully featured, easy to use, low overhead profiler.
- Zipkin - A distributed tracing system gather timing data for disparate services developed by Twitter.
Tools for managing jvm runtime processes
- Capsule - Dead-Simple Packaging and Deployment for JVM Apps.
- CRaSH - The shell for the Java Platform.
- Drip - Fast JVM launching without the hassle of persistent JVMs.
- HotswapAgent - Redefine classes at runtime and skip the redeploy process.
- jvmkill - Agent that forcibly terminates the JVM when it is unable to allocate memory or create a thread.
- Nailgun - Nailgun is a client, protocol, and server for running Java programs from the command line without incurring the JVM startup overhead.
Virtual machines that implement the JVM specification or parts of it.
- Avian - Lightweight highly portable JVM with an option for AOT compilation.
- Dalvik - Android runtime (ART) is the managed runtime used by applications and some system services on Android.
- DCEVM - Modification of Java HotSwap VM with unlimited support for reloading classes at runtime.
- HotSpot - HotSpot virtual machine maintained and distributed by Oracle Corporation.
- IBM J9 - JVM developed by IBM.
- Eclipse OpenJ9 - Eclipse OpenJ9.
- J2ObjC - Translator from Java source to Objective-C code. Keeps shared code between iOS native apps and Android native apps.
- jvm.go - A JVM written in Go.
- ParparVM - An Open Source Java bytecode to C translator for iOS native development. Designed as a part of the Codename One WORA for mobile project.
- MobiDevelop's RoboVM Fork - Ahead of time compiler for JVM bytecode targeting iOS, Mac OSX and Linux.
- Zing - The only JVM that eliminates Java garbage collection pauses for large heap sizes.
- Zulu - The only certified multi-platform build of OpenJDK: Free, 100% open source Java.
Documentation related to JVM
Videos, podcasts and other media related to JVMs
People that share hard-earned, often undocumented, knowledge and data of the inner workings of the JVM
- Aleksey Shipilëv - Developing Oracle/Open JDK/Hotspot and other Java-related technologies.
- Andrey Breslav - Lead Language Designer of Kotlin @ JetBrains.
- Brian Goetz - Java Language Architect at Oracle.
- Ben Christensen - Facebook, Netflix, Apple engineering.
- Brendan Gregg - Cloud performance, kernel engineer, speaker, author.
- Charles Nutter - JRuby guy.
- Claes Redestad - Working with OpenJDK stuff @ Oracle.
- Cliff Click - Creator of the HotSpot Server Compiler.
- Dave Dice - Senior research scientist in the Scalable Synchronization Research Group within Oracle.
- Dávid Karnok - RxJava committer that blogs about advanced RxJava.
- Doug Lea - Author of the Java memory model.
- Gil Tene - Azul Systems.
- Heinz Kabutz - Author of 250+ Java Specialists' Newsletters.
- Ivan Krylov - JVM expert.
- Jake Wharton - Square, Google, open source hacker.
- John Rose - HotSpot developer.
- Jonas Bonér - Founder & CTO of Lightbend.
- Lukas Eder - Blogger. Author of JOOQ.
- Marcus Lagergren - Java language team alumnus.
- Mark Reinhold - Chief Architect, Java Platform Group, Oracle.
- Martin Thompson - Pasty faced performance gangster.
- Martijn Verburg - Java Champion.
- Kirk Pepperdine - Working in high performance and distributed computing for nearly 20 years.
- Nitsan Wakart - Azul Systems.
- Norman Maurer - Netty developer.
- Paul Phillips - Forever undisputed SLOC Scala compiler dev.
- Per Liden - Hacking on the HotSpot JVM at Oracle.
- Peter Lawrey - Innovative developer of high performance Java systems for competitive advantage.
- Rafael Winterhalter - Author of ByteBuddy.
- Richard Warburton - Developer, Speaker, Author.
- Richard Startin - Performance Analyst, developer, blogger.
- Ron Pressler - Parallel Universe. Leading Fibers and Continuations for the JVM.
- Stephen Colebourne - Java Champion. Occasional blogger and speaker. Best known for Joda projects and JSR-310.
- Todd L. Montgomery - Ex-CTO, Ex-NASA researcher, network geek, messaging middleware designer.
- Stéphane Maldini - Project Reactor Lead @Pivotal.
- Stuart Marks - Doctor Deprecator. Java/JDK/OpenJDK developer
- Vladimir Ivanov - hacking HotSpot JVM @ Oracle.
- Viktor Klang - Deputy CTO at Typesafe Inc.