Spring AOP

[Vaibhav Gargs]

In Spring AOP, what kind of weaving is used: Load Time, Compile Time or Run Time? And, how about AspectJ?

[Tim Holloway]

To the best of my knowledge, it's your choice.

I haven't done much with Spring AOP directly, but apparently it's used internally in Spring JPA, so I've had to explicitly specify a weaver in my Tomcat server configuration when using Spring JPA and JavaServer Faces.

[Peter Rooke]

In spring aop it is run time weaving for the beans as you are using dynamic proxies that are returned by the container.  
There are two major limitations of spring aop; it only applies to public methods and only on spring beans (actually its the bean proxies that you use to access the spring beans).
   
I've not used AspectJ much, but have read that it's a more complete solution offering more features and compile time / class load time weaving.
Hopefully you will not be surprised to hear that spring offers aspectj integration.  

Here's a decent article comparing the two; Spring aop vs Aspectj