dprint-plugin-java

A dprint plugin for formatting Java code, inspired by palantir-java-format.

Built as a Rust WASM plugin using tree-sitter-java for parsing.

Installation

Add the plugin to your dprint.json:

{
  "plugins": [
    "https://github.com/speakeasy-api/dprint-plugin-java/releases/latest/download/dprint_plugin_java.wasm"
  ],
  "java": {}
}

Configuration

Option	Type	Default	Description
lineWidth	number	120	Maximum line width
indentWidth	number	4	Spaces per indent level
useTabs	boolean	false	Use tabs instead of spaces
newLineKind	"lf" | "crlf" | "system"	"lf"	Line ending style
formatJavadoc	boolean	false	Format Javadoc comments
methodChainThreshold	number	80	Column threshold for breaking method chains
inlineLambdas	boolean	true	Keep short lambdas on one line

Example configuration:

{
  "java": {
    "lineWidth": 100,
    "indentWidth": 2
  }
}

Supported Constructs

• Declarations: packages, imports, classes, interfaces, enums, records, methods, constructors, fields
• Statements: blocks, if/else, for, enhanced for, while, do-while, switch, try/catch/finally, try-with-resources, return, throw, break, continue, assert, synchronized, labeled statements
• Expressions: binary, unary, method invocation, field access, lambda, ternary, object creation, cast, instanceof, array access, method reference, parenthesized

Development

Prerequisites

• Rust (stable toolchain)
• wasi-sdk (for WASM builds, set WASI_SDK_PATH)

Running Tests

cargo test

Building WASM

export CC_wasm32_unknown_unknown="$WASI_SDK_PATH/bin/clang"
cargo build --release --target wasm32-unknown-unknown --features wasm

The WASM binary will be at target/wasm32-unknown-unknown/release/dprint_plugin_java.wasm.

Testing with dprint

cd examples
dprint check    # verify formatting
dprint fmt      # apply formatting

License

Apache-2.0