JDK main-line development https://openjdk.org/projects/jdk

IntelliJ IDEA & IntelliJ Platform

A high performance caching library for Java

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

jsoup: the Java HTML parser, built for HTML editing, cleaning, scraping, and XSS safety.

A barebones WebSocket client and server implementation written in 100% Java.

Java JsonPath implementation

Test Automation Made Simple

Testcontainers is a Java library that supports JUnit tests, providing lightweight, throwaway instances of common databases, Selenium web browsers, or anything else that can run in a Docker container.

Tiny, easily embeddable HTTP server in Java.

Reactive Streams Specification for the JVM

A reference implementation of a JSON package in Java.

Fibers, Channels and Actors for the JVM

Google Go language IDE built using the IntelliJ Platform

Eclipse Jetty® - Web Container & Clients - supports HTTP/3, HTTP/2, HTTP/1, websocket, servlets, and more

XChange is a Java library providing a streamlined API for interacting with 60+ Bitcoin and Altcoin exchanges providing a consistent interface for trading and accessing market data.

High performance non-blocking webserver

An in-memory file system for Java

OpenTelemetry Java SDK

An HTML to PDF library for the JVM. Based on Flying Saucer and Apache PDF-BOX 2. With SVG image support. Now also with accessible PDF support (WCAG, Section 508, PDF/UA)!

fastutil extends the Java™ Collections Framework by providing type-specific maps, sets, lists and queues.

Cross-platform static analyzer and linter for Swift.

Rich-text area for JavaFX

Transactional schema-less embedded database used by JetBrains YouTrack and JetBrains Hub.

Jansi is a small java library that allows you to use ANSI escape sequences to format your console output which works even on windows.

Java Template Engine

LZ4 compression for Java

Secure and speedy templates for Java and Kotlin.

Multifunctional java deobfuscation tool suite

Simple and clean testing for JavaFX.