Maven Error Prone "error: [<Check>]" Compile Failure - Fix in CI

Error Prone runs inside javac as an annotation-processor-style compiler plugin and promotes bug patterns to errors. A flagged pattern (e.g. [MissingOverride], [EqualsHashCode]) becomes a compile error and fails the build.

What this error means

Compilation fails with error: [<CheckName>] <message> at a file and line, even though the code is valid Java. The Error Prone check name in brackets identifies the bug pattern, not a syntax error.

mvn output

[ERROR] /src/main/java/com/example/Cache.java:[31,5] error: [MissingOverride]
  expected @Override because this method overrides a method in a supertype
    public boolean equals(Object o) {
[ERROR] Failed to execute goal ...:compile (default-compile): Compilation failure

Common causes

A bug pattern flagged as an error

Error Prone detected a likely mistake (missing @Override, an equals without hashCode, a format-string mismatch) and, at error severity, fails the compile.

A new check or stricter severity

Upgrading Error Prone or raising a check’s severity surfaces patterns in existing code that previously compiled.

How to fix it

Fix the flagged pattern

The bracketed check name and message describe the real fix - usually a one-line correction.

Java

// [MissingOverride] - add the annotation
@Override
public boolean equals(Object o) { ... }

Demote a check deliberately if it is a false positive

Lower a specific check’s severity via the compiler args rather than disabling Error Prone wholesale.

pom.xml (compiler)

<compilerArgs>
  <arg>-Xplugin:ErrorProne -Xep:MissingOverride:WARN</arg>
</compilerArgs>

How to prevent it

Run Error Prone on every PR so patterns surface before merge.
Pin the Error Prone version so the active checks are stable.
Demote individual checks deliberately, not the whole plugin.