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javafmt

A fast, opinionated Java code formatter for Java 21+.

echo "class X{}" | javafmt
class X {}

Why​

The Java formatters that exist are either slow or always a language version behind. javafmt uses javac's own parser (com.sun.source.tree), so when new syntax lands in the JDK it's already supported. The CLI ships as a fat JAR and as a platform-native binary via GraalVM native-image.

The style is opinionated on purpose. Every config knob is a debate your team would otherwise have to have. Pick javafmt if you'd rather skip that meeting.

Get started​

What it enforces​

  • 150-character lines, 4-space indent
  • K&R braces (missing braces get auto-added)
  • Member order: static fields -> instance fields -> constructors -> methods by visibility -> nested types
  • Imports: static first, ASCII-sorted, one flat group
  • Ruff-style lint pass: auto-fix what's safe, warn on what isn't

Full spec: Formatting rules.