Apache Maven vs Buck2

Apache Maven is a free build tool for Java projects. It uses a project object model, or POM, and plugins to manage compilation, testing and documentation through a uniform build system. Maven manages dependencies, including transitive dependencies and automatic updates, and can download them from a central repository. Project metadata can produce outputs such as JARs, WARs and distributions. Maven can also generate project information, including changelogs, cross-referenced sources, dependency lists and unit test reports. Java or scripting-language plugins extend it, and it can work with source control systems such as Subversion or Git to manage tag-based releases. It runs on Windows, macOS and Linux. Maven 3.10 and later requires JDK 8 or above to execute, while toolchains can target other JDK versions. Its project layout is opinionated, so projects with unusual structures that cannot be reorganized may have to give up some Maven features or Maven itself. The software is distributed under Apache License 2.0; its listed plan costs nothing.

Buck2 is a free build system from Meta for large-scale repositories that combine multiple programming languages. It uses Starlark rules, a dynamic dependency graph, and incremental actions to support extensible builds. Its language table lists prelude rules for C/C++, Erlang, Go, Haskell, Java, Kotlin, OCaml, Python, and Rust, though usability varies by language. Build actions can run remotely through services exposing Bazel's remote execution API; the project lists BuildBarn, BuildBuddy, EngFlow, and NativeLink as compatible with its distributed compilation support. Buck2 supports filesystem watching and can integrate with Meta's optional Eden virtual filesystem. Rules are hermetic by default and missing dependencies are errors, but local-only build steps are not sandboxed. The project describes Buck2 as early-stage and says it has no stable release tag; its latest binary tag changes with repository pushes. It warns that outside users may encounter rough edges, missing features, and missing toolchains. Source and binaries are available under MIT and Apache-2.0 licenses. The project directs users to GitHub for issue reports and offers a community Discord server.