Using object name with in the <> , as new ArrayList<String> is correct or it is ok to used only <>?

I created generics like below (1) way , but when Sonar gives me error to replace ,it has (2) . I need to know , what is the best and correct way create generics using <> operator .

Noncompliant Code Example

List<String> strings = new ArrayList<String>();  // Noncompliant
Map<String,List<Integer>> map = new HashMap<String,List<Integer>>();  // Noncompliant

Compliant Solution

List<String> strings = new ArrayList<>();
Map<String,List<Integer>> map = new HashMap<>();

Sonar Code Analysis given below warning :

ava 7 introduced the diamond operator (<>) to reduce the verbosity of generics code. For instance, instead of having to declare a List's type in both its declaration and its constructor, you can now simplify the constructor declaration with <>, and the compiler will infer the type.

Note that this rule is automatically disabled when the project's sonar.java.source is lower than 7.

Solution

You are right, using the diamond operator (introduced in Java 7) as:

List<String> strings = new ArrayList<>();
Map<String,List<Integer>> map = new HashMap<>();

is better due to letting the compiler to infer the arguments as per the declared type.