That's because List is an interface, not a class. FYI this works in Scala:
val j = List(1, 2, 3)
It doesn't work for all scala interfaces, and when it is like that, it's often frustrating to find the underlying implementation.
But that's beside the point—OP was pointing out that you can't have generic allocation.
List<Integer>[] j=new List<Integer>[10];
and this is a a serious problem. If generics are correctly implemented, then it should compile.