Java LSP Setup

This command will configure your Java development environment with Eclipse JDT LS and essential tools.

Prerequisites Check

First, verify Java is installed (JDK 21+ recommended):

java -version

Installation Steps

1. Install Eclipse JDT LS Server

macOS (Homebrew):

brew install jdtls

Manual Installation:

1. Download from: https://download.eclipse.org/jdtls/snapshots/
2. Extract to a directory (e.g., ~/.local/share/jdtls)
3. Add to PATH or create a wrapper script

2. Install Build Tools

Maven:

brew install maven

Gradle:

brew install gradle

3. Install Development Tools (Optional)

# Google Java Format
brew install google-java-format

# Checkstyle (usually via Maven/Gradle plugin)

4. Verify Installation

jdtls --version
mvn -version
gradle --version

5. Enable LSP in Claude Code

export ENABLE_LSP_TOOL=1

Verification

Test the LSP integration:

# Create a test project
mkdir -p /tmp/test-java-lsp/src/main/java && cd /tmp/test-java-lsp
echo 'public class Main { public static void main(String[] args) { System.out.println("Hello"); } }' > src/main/java/Main.java

# Create minimal pom.xml
cat > pom.xml << 'EOF'
<project>
  <modelVersion>4.0.0</modelVersion>
  <groupId>test</groupId>
  <artifactId>test</artifactId>
  <version>1.0</version>
</project>
EOF

# Compile
mvn compile

# Clean up
cd - && rm -rf /tmp/test-java-lsp