From the Java Tutorials generics lesson:
In Java SE 7 and later, you can replace the type arguments required to
invoke the constructor of a generic class with an empty set of type
arguments (<>) as long as the compiler can determine, or infer, the
type arguments from the context. This pair of angle brackets,<>, is
informally called the diamond. For example, you can create an instance
ofBox<Integer>with the following statement:
Box<Integer> integerBox = new Box<>();