First I have a question: how is this question of yours different from the other two posts you made:
If they are all the same question worded in different ways, please don't do that!
There are two places you can look for the answer to this, and the other two, questions. First, there is the JSR-168 spec, which you can get from http://jcp.org/en/jsr/detail?id=168.
The other place is to download the JBoss Portal source files and dig through the Java classes.