Free Java thread dump analyzer. Paste jstack output to detect deadlocks, lock contention hot spots, and saturated thread pools, with concrete fixes. Export as PDF. Runs entirely in your browser.

What it looks for

Deadlocks — parses jstack's own "Found one Java-level deadlock" section and shows the blocking cycle directly.
Hot locks — groups BLOCKED threads by the monitor address they're waiting on and identifies the thread currently holding it, so you know exactly where to look.
Pool saturation — groups threads by name prefix (e.g. http-nio-8080-exec-*) and flags pools where most threads are RUNNABLE or BLOCKED, a sign requests are queuing behind a slow pool.

How to capture a thread dump

jstack <pid>, kill -3 <pid> (writes to the process's stdout/log), or trigger one from a JMX/profiler tool. For intermittent issues, take 3-4 dumps a few seconds apart — a single snapshot can't tell you if a BLOCKED thread is stuck or just unlucky timing.

Notes

Everything runs locally in your browser — your thread dump is never uploaded.
The PDF export opens your browser's print dialog — choose "Save as PDF" as the destination.

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