Formerly known as Hudson, Jenkins is the de facto standard for the CI server in the Java ecosystem, and is also becoming popular in other communities. Its primary task is continuous integration. It checks project health on a regular basis using automated build and test scripts. Jenkins offers an extensible design and is based on the plugin, so that it can offer a simplified UI or specialized features for some specific use cases.
Integration used to be a project management phase, which gets started after the code development has been completed, to put the software components together and pass some tests to ensure that the project goals are achieved. This used to be complex, time consuming, and used to reveal bugs that had a huge impact on codebase because they had been detected late.
As an Agile software development evangelist said, "If it hurts too much, do it more, on smaller assets", so Extreme Programming has promoted CI. The principle of CI is to run the integration...