javax.script Engine for JavaScript Based on V8

This is a V8-based javax.script engine for Java.

Prerequisites to build

• git
• make
• JDK 25 (set JAVA_HOME env. var to that JDK)
• Typical build utilities: bash, tar, zip, curl (often already present)
• Python 3 (required by V8 tooling)
• C/C++ toolchain for your OS
  • Linux: gcc/g++ or clang, plus common build packages (varies by distro)
  • macOS: Xcode Command Line Tools (xcode-select --install)

Quick Checks

git --version
make --version
python3 --version
${JAVA_HOME}/bin/java -version

Build and Test

• Clone the depot_tools into a directory outside this repo. This provides key tools used to fetch and build V8 (gclient, fetch, gn, ninja...).

  git clone https://chromium.googlesource.com/chromium/tools/depot_tools

• Set the depot_tools repo directory in PATH

  export PATH="<your-depot-tools-dir>:$PATH"

• To fetch/sync the V8 sources, specifically version 14.4.221 and dependencies:

  make get-v8

• To do a clean build:

  make clean all

• (Optional) To run jtreg tests:

  export JT_HOME=<your_jtreg_home_dir>
  make test

• To run the interactive shell:

  bash jjs.sh
  v8> java.lang.System.out.println("hello world")
  hello world
  v8> java.lang.System.exit(0)

• There are samples in the samples directory. To run a sample script:

  bash jjs.sh samples/helloworld.js

• There are also Java samples. To run a Java sample:

  bash run-java-sample.sh samples/HelloWorld.java

• To create a distribution bundle:

  make dist bundles

  The resulting .tar.gz bundle is written to build/<platform-specific-dir>/bundles/.

Enabling V8 flags via environment variable

JVMV8_FLAGS environment variable can be set with V8 flags

To enable dumping heap snapshot on out of memory crash

export JVMV8_FLAGS=--heap-snapshot-on-oom

To enable tracing/logging,

export JVMV8_FLAGS=--trace

export JVMV8_FLAGS=--trace-exception

export JVMV8_FLAGS=--log-all