Two years ago, Bob Lee and Kevin Bourrillion open sourced Google Guice 1.0, a lightweight Java dependency injection framework. Guice takes the pain out of writing and maintaining Java applications big and small. Guice has gained a great deal of traction both inside and outside of Google. Almost every Java-based application at Google is also a Guice-based application; the list includes AdWords, Google Docs, Gmail, and even YouTube. Open source users run Guice in everything from file-sharing software to ATMs. They've even written two books about this Jolt-award-winning framework.

Today, we're releasing Guice 2. The minimally-sized API extensions introduced by Guice 2 will have a majorly positive impact on the size and maintainability of your code. We closely scrutinized each addition, carefully balancing maintainability and flexibility. Here are a few of my favorite new features:

• Provider methods eliminate the boilerplate of manually-constructed dependencies.
• Module overrides allow you to tweak a production module for a unit test or QA deployment.
• Private modules enable compartmentalized configuration, simplifying module reuse.

Guice works with Java SE, Java EE, Google App Engine, Android, and even Google Web Toolkit (via GIN).

References
Guice 2.0 Release Notes
Downloads
User's Guide
Javadoc

By Jesse Wilson, Google Developer Team