Open Source Java Build Tools

Build and test software of any size, quickly and reliably. Bazel only rebuilds what is necessary. With advanced local and distributed caching, optimized dependency analysis and parallel execution, you get fast and incremental builds. Build and test Java, C++, Android, iOS, Go and a wide variety of other language platforms. Bazel runs on Windows, macOS, and Linux. Bazel helps you scale your organization, codebase and Continuous Integration system. It handles codebases of any size, in multiple repositories or a huge monorepo. Easily add support for new languages and platforms with Bazel's familiar extension language. Share and re-use language rules written by the growing Bazel community. Bazel is the common build tool throughout Pinterest and has been instrumental in achieving fast, reproducible builds across our programming languages and platforms.

Buck is a build system developed and used by Facebook. It encourages the creation of small, reusable modules consisting of code and resources, and supports a variety of languages on many platforms. Buck builds independent artifacts in parallel to take advantage of multiple cores on your machine. Further, it reduces incremental build times by keeping track of unchanged modules so that the minimal set of modules is rebuilt. Buck only uses the declared inputs, which means everybody gets the same results. Buck looks at the contents of your inputs, not their timestamps to figure out what needs to be built. As a result, incremental builds should always be correct, so there's no need to perform a clean build. With buck query, you can better understand your dependencies and what is required to build your product. With buck project, your project can be better understood by your IDE, making you and your team more productive.