This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
T and E are just conventions. T stands for type, and E stands for element. However, you can use valid Java identifiers for the type parameters.
I believe that the example in question was an example of what not to do. However, they are pointing out that there is no confusion on the part of the compiler if you use the same identifier for the type parameter as the name of the class and/or the name of the method.