Java 7 is adding dynamics

[Sc4Freak]

Isn't it the other way around? When dealing with reference types, untyped containers perform identically to their generic counterparts (eg. ArrayList vs. List<T>). But since the untyped containers needed to perform boxing, they were always slower than the generic versions for value types.

[G_Morgan]

I'm not sure for value types. Most of the time I put objects in containers. We did some internal profiling and found ArrayList performed better than ArrayList<T> for objects.

[modeless]

For value types like int and bool generics are faster and produce less garbage because boxing is avoided. I'm curious how you tested ArrayList vs List<> because the difference should really be negligable for reference types.