Alibaba Java Diagnostic Tool Arthas/Alibaba Java诊断利器Arthas

A Java 8+ Jar & Android APK Reverse Engineering Suite (Decompiler, Editor, Debugger & More)

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)

Java dataframe and visualization library

VisualVM is an All-in-One Java Troubleshooting Tool

Twitter4J is an open-source Java library for the Twitter API.

https://openjdk.org/projects/jmc OpenJDK Mission Control, a production time profiling and diagnostics tools suite.

Programs for producing static and dynamic (runtime) call graphs for Java programs

Byteman Project main repo

A Java GUI tool for analyzing NMON and other system stats files

XOM™ is a new XML object model. It is an open source (LGPL), tree-based API for processing XML with Java that strives for correctness, simplicity, and performance, in that order.

Gravel is a Smalltalk implementation for the JVM

OGDL for Java