In Java 10 Local-Variable Type Inference was introduced. It allows you to omit the expected type of a variable by declaring it with the var keyword.

While it is not always possible or cleaner to use this new way of declaring a variable, when the type on the left is the same as the one on the right in an assignment, using the var will result in a more concise code.

This rule reports an issue when the expected type of the variable is the same as the returned type of assigned expression and the type can be easily inferred by the reader, either when the tye is already mentioned in the name or the initializer, or when the expression is self-explained.

Noncompliant Code Example

MyClass myClass = new MyClass();

int i = 10; // Type is self explained

MyClass something = MyClass.getMyClass(); // Type is already mentionned in the initializer

MyClass myClass = get(); // Type is already mentionned in the name{code}

Compliant Solution

var myClass = new MyClass();

var i = 10;

var something = MyClass.getMyClass();

var myClass = get();

See