Look for qualified this usages in the same class.

Examples:

    public class ToStringDemo extends Super{
        private String secondName;
        @Override
        public String toString() {
            return super.toString() + "ToStringDemo{" + "secondName='" + secondName + '\'' + '}';
        }
    }
    class Super {
        private String firstName;
        @Override
        public String toString() {
            return "Super{" + "firstName=" + firstName + '\'' + '}';
        }
    }