OpenJDK7: What essential ADTs are not Implemented in OpenJDK7?

What Abstract Datatypes should be added to OpenJDK7 ?

If you look at these two links you will see what some people feel is missing:

• http://commons.apache.org/collections/
• http://code.google.com/p/google-collections/

My favourite missing one is Bag... it is easy to implement, but annoying to have to implement it.

Mulimaps would also nice to have in the standard packages.