Initializing a collection [duplicate]

Question

What is the difference between the following two statements, in initializing an ArrayList?

ArrayList<String> a = new ArrayList<String>();
ArrayList<String> a = new ArrayList<>();

Answer 1

Before Java 1.7, only this one is permitted:

ArrayList<String> a = new ArrayList<String>();

And in 1.7, this is added, which is the same but shorter: (all programmers are lazy)

ArrayList<String> a = new ArrayList<>();