Compilation fails because the hashCode method is not overridden.
A HashSet could contain multiple Person objects with the same name.
All Person objects will have the same hash code because the hashCode method is not overridden.
If a HashSet contains more than one Person object with name="Fred", then removing another Person, also with name="Fred", will remove them all.
第1题:
public class Person { private String name, comment; private int age; public Person(String n, int a, String c) { name = n; age = a; comment = c; } public boolean equals(Object o) { if(! (o instanceof Person)) return false; Person p = (Person)o; return age == p.age && name.equals(p.name); } } What is the appropriate definition of the hashCode method in class Person?()
第2题:
public class Person { private name; public Person(String name) { this.name = name; } public int hashCode() { return 420; } } Which is true?()
第3题:
A.Compilation will succeed for all classes and interfaces.
B.Compilation of class C will fail because of an error in line 2.
C.Compilation of class C will fail because of an error in line 6.
D.Compilation of class AImpl will fail because of an error in line 2
第4题:
Which of the following statements are true?()
第5题:
Given: String value = getServletContext().getInitParameter("foo"); in an HttpServlet and a web applicationdeployment descriptor that contains:
第6题:
1. public class Person { 2. private String name; 3. public Person(String name) { this.name = name; } 4. public boolean equals(Person p) { 5. return p.name.equals(this.name); 6. } 7. } Which is true?()
第7题:
11. public static void main(String[] args) { 12. Object obj = new Object() { 13. public int hashCode() { 14. returns 42; 15. } 16. }; 17. System.out.println(obj.hashCode()); 18. } What is the result? ()
第8题:
A.True
B.Not true
C.An exception is thrown at runtime.
D.Compilation fails because of an error at line 12.
E.Compilation fails because of an error at line 19.
第9题:
Which two statements are true regarding the return values of property written hashCode and equals methods from two instances of the same class?()
第10题:
public class Person { private name; public Person(String name) { this.name = name; } public boolean equals(Object o) { if( !o instanceof Person ) return false; Person p = (Person) o; return p.name.equals(this.name); } } Which is true?()