class Sock { String size; String color; public boolean equals(Object o) { Sock s = (Sock) o; return color.equals(s.color); } // insert code here } 哪两个满足 hashCode 的约定?()
第1题:
A.public int compareTo(Object o){/*more code here*/}
B.public int compareTo(Score other){/*more code here*/}
C.public int compare(Score s1,Score s2){/*more code here*/}
D.public int compare(Object o1,Object o2){/*more code here*/}
第2题:
Given: 3.public class MyTagHandler extends TagSupport { 4.public int doStartTag() { 5.// insert code here 6.// return an int 7.} 8.// more code here ... 18.} There is a single attribute foo in the session scope. Which three code fragments,inserted independently atline 5,return the value of the attribute?()
第3题:
A.publicinthashCode(){return343;}
B.publicinthashCode(){returnsize.hashCode();}
C.publicinthashCode(){returncolor.hashCode();}
D.publicinthashCode(){return(int)(Math.random()*1000);
第4题:
Given the following code, which method declarations, when inserted at the indicated position, will not cause the program to fail compilation?() public class Qdd1f { public long sum(long a, long b) { return a + b; } // insert new method declaration here }
第5题:
class Sock2 { String color; public boolean equals(Object o) { return color.equals(((Sock2)o).color); } } class TestSocks { public static void main(String [] args) { Sock2 s1 = new Sock2(); s1.color = "blue"; Sock2 s2 = new Sock2(); s2.color = "blue"; if (s1.equals(s2)) System.out.print("equals "); if (s1 == s2) System.out.print("== "); } } 结果为:()
第6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7题:
Which statements concerning the following code are true?() class a { public a() {} public a(int i) { this(); } } class b extends a { public boolean b(String msg) { return false; } } class c extends b { private c() { super(); } public c(String msg) { this(); } public c(int i) {} }
第8题:
A.无法确定
B.publicbooleanequals(Objecto){Socks=(Sock)o;returnsize.equals(s.size);}
C.publicbooleanequals(Objecto){Socks=(Sock)o;returncolor.equals(s.color);}
D.publicbooleanequals(Objecto){Socks=(Sock)o;returnsize.equals(s.size)&&color.equals(s.color);}
第9题:
public class Person { private name; public Person(String name) { this.name = name; } public int hashCode() { return 420; } } Which is true?()
第10题:
10. interface Foo { int bar(); } 11. public class Sprite { 12. public int fubar( Foo foo) { return foo.bar(); } 13. public void testFoo() { 14. fubar( 15. // insert code here 16.); 17. } 18. } Which code, inserted at line 15, allows the class Sprite to compile?()