这样重写equals方法可以不,该怎么解决

public class Student {    private String name;    private int age;    public boolean equals(Object o) {        boolean flag = false;        if (o != null) {            if (this == o) {                flag = true;            } else {                if (o instanceof Student) {                    Student s = (Student) o;                    if (this.name.equals(s.name) && this.age == s.age) {                        flag = true;                    }                }            }        }        return flag;    }    public static void main(String[] args) {        Student s1 = new Student();        s1.name = "kaka";        s1.age = 10;        Student s2 = new Student();        s2.name = "kaka";        s2.age = 10;        System.out.println(s1.equals(s2));    }}

public class Student{    private String name;    private int age;    public boolean equals(Object o)    {        boolean flag = false;        if(o != null)        {            if(this == o)            {                flag = true;            }            else if(o instanceof Student)            {                Student s = (Student)o;                if(this.name.equals(s.name) && this.age == s.age)                {                    flag = true;                }            }        }                return flag;    }    public static void main(String[] args)    {        Student s1 = new Student();        s1.name = "kaka";        s1.age = 10;        Student s2 = new Student();        s2.name = "kaka";        s2.age = 10;        System.out.println(s1.equals(s2));    }}
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Java code
    public boolean equals(Object obj) {        if (obj == this)            return true;        if (!(obj instanceof Student))            return false;        Student s = (Student) obj;        return this.name.equals(s.name) && this.age == s.age;    }
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用o.getClass()==Student.class 会不会更精确一点
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还可以更好一点
Java code
public boolean equals(Object obj) {  if (this == obj) return true;    if (obj == null) return false;  if (getClass() != obj.getClass()) return false;   //注意,这里如果用 (obj instanceof Student) 来判断的话,那么Student所有的子类  //的 equals 方法就不能有改变  Student s = (Student) obj;  return name.equals(s.name) && age == s.age;  }
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Java code
    public boolean equals(Object obj) {        if (obj == this) return true;        if (obj == null) return false;        if (obj.getClass() != this.getClass()) return false;        Student other = (Student) obj;        return (other.name == null ? this.name == null : other.name.equals(this.name)) &&               (other.age == this.age);    }