errorprone

Error Prone is an open-source static analysis tool for Java designed to catch common programming mistakes at compile time. It originated at Google to improve code quality in large Java codebases and is now maintained publicly. It operates as a plug-in to the Java compiler (javac) by providing a set of BugCheckers that analyze the abstract syntax tree and control flow during compilation. When a checker detects a pattern likely to cause an error, it reports a diagnostic message, often surfaced as a compilation error or warning and may include suggested fixes.

Error Prone can be used with standard build tools such as Maven and Gradle. It provides or integrates with the Error Prone compiler, allowing teams to customize which checks are enabled, adjust severities, and enable automated fixes for certain patterns. The checks are designed to be precise and minimize false positives, while targeting issues that frequently lead to bugs.

Checks cover topics such as null handling, equals and hashCode contracts, API misuse, threading concerns, and other correctness issues that are common sources of bugs. The project maintains a curated and evolving set of BugCheckers intended to improve safety and reliability without unduly slowing development.

Error Prone is licensed under the Apache License 2.0. It complements other static analysis tools in the Java ecosystem and is widely used in large codebases to enforce safer coding patterns at compile time. It remains a practical option for teams seeking early feedback on potential defects and more actionable diagnostics than standard compiler warnings.