Appending String.valueOf() to a String decreases the code readability. The argument passed to String.valueOf() should be directly appended instead.

The following code:

public void display(int i){
  System.out.println("Output is " + String.valueOf(i));    // Non-Compliant
}

should be refactored into:

public void display(int i){
  System.out.println("Output is " + i);                    // Compliant
}