Introducing Error Prone: Google’s Open‑Source Java Static Analysis Tool and How to Use It

Error Prone is an open‑source static analysis tool for Java, released by Google in 2015, which can be integrated into existing build processes to detect code defects during compilation, especially useful for Java and Android projects.

Key features include non‑intrusive hooking into the standard build pipeline, immediate feedback on errors, and detailed fix suggestions that can be leveraged to build custom checks.

To use Error Prone, add the appropriate Gradle plugin (e.g., gradle-errorprone-plugin) or Maven/ANT configuration as described in the official documentation. The plugin requires Gradle 2.0+ and a JDK 7 or newer that matches the javac version.

Checks are controlled via bug‑template patterns; you can enable or disable specific checks and set their severity using the -Xep:<checkName>[:severity] compiler option, where severity can be OFF, WARN, or ERROR.

Example: -Xep:StringSplitter:WARN Exclude paths to reduce noise, e.g., -XepExcludedPaths=**/build/generated/** Compared with FindBugs, Error Prone offers advantages such as active Google backing, clear remediation guidance, a bug‑pattern based checking model, early detection by hooking into compilation, and extensibility (e.g., NullAway). Its drawbacks include Java‑only support, requirement of JDK 7+, limited built‑in checks, and increased compilation time.

Adopting Error Prone can improve code quality early in development, complement other tools like FindBugs in CI pipelines, and is supported by an active open‑source community including companies like Google, Uber, and Flipboard.

References: GitHub – error‑prone , Gradle plugin , Official site .