HashMap initialization parameters (load / initialcapacity)

Question

What values should I pass to create an efficient HashMap / HashMap based structures for N items?

In an ArrayList, the efficien

Answer 1

It's safe in most cases of List and Map initialization to make the List or Map with the following size params.

List(numElements + (numElements / 2));
Map(numElements + (numElements / 2));

this follows the .75 rule as well as saves a little overhead over the * 2 operation described above.