The Whyline for Java, an interactive debugging tool that lets you ask "why" questions about program out.

GZoltar - Java Library for Automatic Debugging http://www.gzoltar.com

Java debugger front-end

SOMns: A Newspeak for Concurrency Research

Full Featured Google Chrome Dev Tools to JavaFX WebView browser debugging.

Bouquet is a java / android library to help debug and log various data when executing RxJava2 Observable, Flowable, Single, Maybe and Completable.

A simple scripting frontend for the Java Debugger Interface

BugSnag error reporting for Java.

Simple tool to MITM your TCP connections to debug and test your software

Bil Lewis' Omniscient Debugger for Java.

Custom java agent for production debugging as presented by Tal Weiss from Takipi @ JavaOne '14 SF

🔥BistouryX是基于Bistoury去哪儿网的java应用生产问题诊断工具，提供了一站式的问题诊断方案

Lumigo's JVM Distributed Tracing and Performance Agent

Lightweight, fast, Java-centric Lua interpreter written for JME and JSE, with string, table, package, math, io, os, debug, coroutine & luajava libraries, JSR-223 bindings, all metatags, weak tables and unique direct lua-to-java-bytecode compiling.

NativeJDB bridges the gap between the Java Debugger (JDB) framework available in modern IDEs and native debugging via GNU Project debugger (GDB).

Java Agent for debugging common libgdx related issues.

Convert any Java object to JSON for easier debugging

A tool to run and debug locally AWS Lambda functions authored in JAVA

Time travelling Java debugger

A generic Java implementation of Andreas Zeller's delta debugging algorithm