Useless parentheses should be removed. Example:
public class Foo {

   private int _bar1;
   private Integer _bar2;

   public void setBar(int n) {
      _bar1 = Integer.valueOf((n)); // here
      _bar2 = (n); // and here
   }

}

This rule is deprecated, use {rule:squid:UselessParenthesesCheck} instead.