关于方法覆盖的问题

[ywuque]

class Student1
{
int age;
String name;
boolean equals(Object obj)
{
if(obj instanceof Student1)
{
return true;
Student1 stu=(Student1)obj;
if(this.age==stu.age&&this.name==stu.name)
return true;
else
return false;
}
else
return false;
}
public static void main(String [] args)
{
Student1 stu1=new Student1();
Student1 stu2=new Student1();
stu1.age=12;
stu1.name="aaa";
stu2.age=12;
stu2.name="aaa";
if(stu1.equals(stu2))
System.out.println("stu1 is equals stu2!");
else
System.out.println("stu1 is not equals stu2");
}
}
-----------------------------------------------

--------------------配置: <默认>--------------------
F:\4\Student1.java:5: equals(java.lang.Object) in Student1 cannot override equals(java.lang.Object) in java.lang.Object; attempting to assign weaker access privileges; was public
boolean equals(Object obj)
^
1 error

[czlt86]

是不是应该将访问权限变为public?因为JAVA不可以将所覆盖的方法的访问权限变得比父类的小

[宋玮-深圳]

对

[ywuque]

public boolean equals(Object obj){}
是这样么？

[IhaveGotYou]

楼主的错误不少
1)return 执行后(return true;),

Student1 stu=(Student1)obj;
if(this.age==stu.age&&this.name==stu.name)
return true;
else
return false;

这部分就不会执行了
2)equals()方法不是你那样实现的,应该

if(obj==null)
  return false;
if(obj==this)
  return true;
if(obj instanceof Student1)
{
  Student1 stu=(Student1)obj;
  return stu.age==this.age && stu.name.equals(this.name);
}
else 
return false;
} 

3)同时，还应该实现hashCode(),事例代码如下:

public int hashCode(){
  int hash=1;
  hash=hash+31*age;
  hash=hash+29*(name==null?0:name.hashCode());
  return hash;
  }

[ywuque]

谢谢