Continuous integration tools

One of the popular VCS tools is Git (https://git-scm.com). A developer uses Git to check-in and check-out code all the time. There are various hosting Git services, including GitHub (https://github.com) and Bitbucket (https://bitbucket.org). These allow you to create and save your Git repositories and collaborate with other users over the internet. The following screenshot shows a sample pull request on GitHub:

The build server has a lot of variation. Jenkins (https://jenkins.io) is one of the most well established applications, along with TeamCity (https://www.jetbrains.com/teamcity/). As well as build servers, you also have hosted services, otherwise known as Software as a Service (SaaS), such as Codeship (https://codeship.com) and Travis CI (https://travis-ci.org). SaaS can integrate with other SaaS tools. The build server is capable of invoking external commands, such as unit test programs. This makes the build server a key tool within the CI pipeline.

The following screenshot shows a sample build using Codeship. We check out the code from GitHub and invoke Maven for building (mvn compile) and unit testing (mvn test) our sample application: