Menu

Individual skill

java-debugging

Debug Java applications systematically: JDWP remote debugging, jdb, VS Code and IntelliJ attach, debugging Maven/Gradle tests, Spring Boot and Quarkus dev mode, containers, breakpoints/logpoints, and reading stack traces. Use when the user needs to find the cause of a Java bug, exception, wrong behavior, or failing test, or asks how to attach a debugger.

skills/java-debugging/SKILL.md

Read pinned source

Source commit edbecfa9099c4addae1f500cca1ac067204b30fd

What was checked

Matches the observed repository HEAD
Yes
Scanner rules are current
Yes
Repository scan complete
No
Skill scan complete
No
Observed behavior
Network or broad shell
Last checked
Nov 4, 2026

These are observations at the recorded commit, not a guarantee of safety. Review the source before running it.

Install this skill

Choose an agent in your Stack or copy a command below. Commands fetch the pinned commit and copy only this skill directory. Existing destinations are refused. Copying a command does not install anything.

An install command is unavailable: current rules, complete repository and skill scans, an eligible behavior level and a permitted license are required.

Repository context

Repository stars (not skill ratings)
40,864
Repository last updated
Nov 6, 2026
License
MIT

Observed agent integration: No specific integration evidence. Standard SKILL.md installation does not imply verified compatibility.

Files and excerpt

File metadata and permitted, redacted excerpts come from the recorded scan. Source links are pinned to that commit.

Browse files
Read excerpt

# Java Debugging

Find the root cause of a Java defect with a reproducible, hypothesis-driven loop, and attach a debugger safely when logs are not enough.

## Safety rules

- Bind JDWP to loopback only (`127.0.0.1`). Never bind `*:5005` on a reachable network; use an SSH tunnel or `kubectl port-forward` for remote hosts.
- Use `suspend=n` for running applications. `suspend=y` is acceptable only for short local test runs bound to loopback (waiting for the IDE to attach). Never leave a debug agent enabled on production; JDWP gives full code execution to whoever connects.
- Do not attach a debugger to production without explicit user instruction. Prefer reproducing locally or use read-only diagnostics (see the `java-diagnostics` skill).
- `JAVA_TOOL_OPTIONS` is picked up by every JVM started in that environment (build tools, forked test JVMs, child processes), causing `Address already in use` clashes. Prefer scoping the flag to the one process you want to debug.

## Method

Reproduce deterministically, minimize, read the evidence ([stack traces](references/stack-traces.md)), test one falsifiable hypothesis with the least intrusive tool (log line or logpoint before breakpoints), then add a regression test and remove debug flags and temporary logging.