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 type is already mentioned in the name or the initializer, or when the expression is
self-explanatory.
Noncompliant code example
MyClass myClass = new MyClass();
int i = 10; // Type is self-explanatory
MyClass something = MyClass.getMyClass(); // Type is already mentioned in the initializer
MyClass myClass = get(); // Type is already mentioned in the name
Compliant solution
var myClass = new MyClass();
var i = 10;
var something = MyClass.getMyClass();
var myClass = get();