java集合框架(习题与答案)资料

@Override

public int hashCode() {

final int prime = 31;

int result = 1;

result = prime * result + age;

return result;

}

@Override

public boolean equals(Object obj) {

if (this == obj)

return true;

if (obj == null)

return false;

if (getClass() != obj.getClass())

return false;

Worker1 other = (Worker1) obj;

if (age != other.age)

return false;

return true;

}

@Override

public String toString() {

// TODO Auto-generated method stub

return name+\

}

}

14. (泛型)使用泛型和Map.Entry 接口,改写第12 题的前4 问 15. *(List)写出下面程序的输出结果 import java.util.*; class MyClass{ int value;

public MyClass(){}

public MyClass(int value){ this.value = value; } public String toString(){ return “”+value; } }

public class TestList{

public static void main(String args[]){ MyClass mc1 = new MyClass(10);

MyClass mc2 = new MyClass(20);//实例化的对象实际上就是一个对象的地址,

//list中保存的是对象的引用,因此mc4,mc1,和list下标为1的对象都是指向的同一个对象

MyClass mc3 = new MyClass(30); List list = new ArrayList(); list.add(mc1); list.add(mc2); list.add(mc3);

MyClass mc4 = (MyClass) list.get(1)//这句话实际上就是把mc4指向了mc2对象的那个地址 MyClass mc4=(MyClass)mc2; mc4.value = 50;

for(int i = 0; i

16. *(Set,HashSet,空指针)有下面代码 import java.util.*;

class Student { int age;

String name;

public Student(){} </

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