Jenkins is an open-source automation server most widely used for continuous integration: it watches a source repository, builds the software whenever changes arrive, runs the test suite, and reports the results so that integration problems surface quickly. It is written in Java and is extended through a large ecosystem of plugins that connect it to version-control systems, build tools, and deployment targets.
The project began life as Hudson, started by Kohsuke Kawaguchi while he worked at Sun Microsystems, with development beginning around 2005. After Oracle acquired Sun, a dispute arose over control of the “Hudson” name. In a January 2011 post on the project’s own site, core contributors including Andrew Bayer, Kohsuke Kawaguchi, and Sacha Labourey proposed renaming the project to Jenkins, arguing that under Oracle’s trademark “Hudson as a project would be beholden to Oracle’s whims for its continued use of its own name.”
The community voted to adopt the new name, and the bulk of the developers and the existing project momentum moved to Jenkins, while Oracle continued a separate Hudson project for a time. The renamed Jenkins project carried forward the same code lineage and Kawaguchi’s leadership.
Jenkins became the default self-hosted CI server for a large share of the software industry, especially in organizations that wanted to run their own build infrastructure rather than depend on a hosted service. Its plugin model let teams assemble pipelines spanning compilation, testing, packaging, and deployment, making it a foundational tool in the spread of continuous integration and, later, continuous delivery practices.