Generics understanding - very concise
June 3rd, 2008 by Boogie
You can find a very concise article about Java Generics on IBM’s website :
http://www.ibm.com/developerworks/library/j-jtp01255.html
It explains quite nicely why Generics are the way they are. It touches type erasure, covariance, T type contructor, and others ( still reading 
).