"SCJP 1.6版考題 200" 修訂間的差異

於 2013年3月27日 (三) 17:05 的最新修訂

Given:
11.  public class Person{
12.       private String name;
13.       public Person(String name){
14.                   this.name = name;
15.        }
16.       public boolean equals(Object o){
17.                  if(!(o instanceof Person)) return false;
18.                  Person p = (Person)o;
19.                  return p.name.equals(this.name);
20.        }
21.   }

Which statement is true?

  A. Compilation fails because the hashCode method is not overridden.
  B. A HashSet could contain multiple Person objects with the same name.
  C. All Person objects will have the same hash code because the hashCode method is not overridden.
  D. If a HashSet contains more than one Person object with name="Fred", then removing another Person, also with name="Fred", will remove them all.