Initializing arraylist without object type - JAVA [duplicate]

Answer 1

In your second example, Java assumes the type is myObject. So there is still a type.

Answer 2

Both pieces of code are equivalent and create ArrayLists with a type (myObject in your example):

List<myObject> obj = new ArrayList<myObject>();

List<myObject> obj = new ArrayList<>();

However the second example uses the diamond operator (<>) introduced in Java 7. It adds type inference and reduces the verbosity in the assignments.

---

See the following quote from the documentation:

You can replace the type arguments required to invoke the constructor of a generic class with an empty set of type parameters (<>) as long as the compiler can infer the type arguments from the context. This pair of angle brackets is informally called the diamond.

For example, consider the following variable declaration:

Map<String, List<String>> myMap = new HashMap<String, List<String>>();

In Java SE 7, you can substitute the parameterized type of the constructor with an empty set of type parameters (<>):

Map<String, List<String>> myMap = new HashMap<>();