Guice

http://code.google.com/p/google-guice/
Google公司的Bob lee开发的轻量级IoC容器，其特点是：
1、速度快，号称是spring的100倍速度
2、无配置文件，实用JDK5.0的annotation描述组件依赖，简单，而且有编译器检查和重构支持
3、简单，代码量很少
http://code.google.com/p/google-guice/wiki/SpringComparison
这是Google guice和spring IoC容器的对比
另外xwork2.0已经集成了Google guice容器了。
http://docs.google.com/Doc?id=dd2fhx4z_5df5hw8
这是Google guice的快速入门文档，用起来挺简单的。
Guice
Put simply, Guice alleviates the need for factories and the use of new in your Java code. Think of Guice's @Inject as the new new. You will still need to write factories in some cases, but your code will not depend directly on them. Your code will be easier to change, unit test and reuse in other contexts.
Guice embraces Java's type safe nature, especially when it comes to features introduced in Java 5 such as generics and annotations. You might think of Guice as filling in missing features for core Java. Ideally, the language itself would provide most of the same features, but until such a language comes along, we have Guice.
Guice helps you design better APIs, and the Guice API itself sets a good example. Guice is not a kitchen sink. We justify each feature with at least three use cases. When in doubt, we leave it out. We build general functionality which enables you to extend Guice rather than adding every feature to the core framework.
Guice aims to make development and Debugging easier and faster, not harder and slower. In that vein, Guice steers clear of surprises and magic. You should be able to understand code with or without tools, though tools can make things even easier. When errors do occur, Guice goes the extra mile to generate helpful messages.
For an introduction to Guice and a comparison to new and the factory pattern, see Bob Lee's video presentation. After that, check out our user's guide.
We've been running Guice in mission critical applications for over a year, and now you can, too. We hope you enjoy it as much as we do.