Watson

Watson is a browser-based, offline JVM thread dump and CPU usage analyzer.

It helps investigate JVM performance problems by grouping similar threads, identifying stuck or CPU-heavy threads, showing monitor contention, visualising stack traces and flame graphs. Its filtering tools help focus the analysis on relevant data.

See screenshots.md for examples of Watson's analysis views.

Getting data

For the most useful analysis, capture both:

• Java thread dumps
• CPU usage output from top

For Atlassian products, the easiest option is to generate a support zip and load the files from:

jfr-bundle/atst_in_product_diagnostic_<timestamp>/threaddumps

You can also collect data manually, including for non-Atlassian applications, with the Atlassian Support scripts.

Development

Prerequisites

• Node.js 24 or later
• Docker, for end-to-end tests
• Corepack, included with supported Node.js releases

corepack enable
yarn install

Run locally

yarn start

Open http://localhost:3000/ in a browser.

Useful commands

Command	Description
yarn start	Start the development server
yarn build	Type-check and create a production build
yarn lint	Run type checks and auto-fix lint and style issues
yarn test	Run unit tests in watch mode
yarn test:coverage	Run unit tests once with coverage
./e2e/run-in-docker.sh	Run end-to-end tests in the pinned Linux Playwright container
./e2e/run-in-docker.sh --update-snapshots	Update visual-test snapshots in the same container used by CI
yarn serve	Preview an existing production build locally

Before running or updating visual tests, fetch the committed screenshot baselines:

git lfs pull

See e2e/README.md for focused visual-test and benchmark commands.