在学java中的object里的equals，遇到问题，总是报错

class Student{
    //学号
    int no;
    //学校
    String school;
    
    public Student() {
        
    }
    
    public Student(int no, String school) {
        super();
        this.no = no;
        this.school = school;
    }

    //重写toString
    public String toString() {
        return "Student [学号" + no + ", 所在学校名字" + school + "]";
    }


    //当一个学生学号和学校相同时，表示同一个学生
    public boolean equals(Object obj) {
        if(obj = null || !(obj instanceof Student)) return false;
        if(this == obj) return ture;
        Student s = (Student)obj;
        return this.no = s.no && this.school.equals(s.school);
    }
    
}

   public boolean equals(Object obj) {
        if(obj = null || !(obj instanceof Student)) return false;
//是true而不是ture
        if(this == obj) return ture;
        Student s = (Student)obj;
//基本数据类型相等使用的是==判断，而不是=
        return this.no = s.no && this.school.equals(s.school);
    }

    //当一个学生学号和学校相同时，表示同一个学生
    public boolean equals(Object obj) {
        if(obj == null || !(obj instanceof Student)) return false;
        if(this == obj) return true;
        Student s = (Student)obj;
        return this.no == s.no && this.school.equals(s.school);
    }

还是没办法解决object不能被强转，那我要怎么继续写下面的东西