java 通用构造函数未定义

Question

I am learning java and generics and stuck in some problem. I have read all the problems on generic posted on Stackoverflow but couldn't understand why this error occurs

class Student{

    String name;
    float marks;

    Student(String name,float marks){
        this.name = name;
        this.marks = marks;
    }

}

public class GenericClassEx<T> {
    
    T obj;
        GenericClassEx(T data){
       
        this.obj = data;
    }

    public T getObject(){
        return this.obj;
    }

    public static void main(String[] args) {
        Float d = new Float(10);
        GenericClassEx<Student> iobj= new GenericClassEx <Student> ("prince",d);
        System.out.println(iobj.getObject());
    }

}

when i run this code it says

GenericClassEx.java:28: error: constructor GenericClassEx in class GenericClassEx<T> cannot be applied to given types;
        GenericClassEx<Student> iobj= new GenericClassEx <Student> ("prince",d);
                                      ^
  required: Student
  found: String,Float
  reason: actual and formal argument lists differ in length
  where T is a type-variable:
    T extends Object declared in class GenericClassEx
Note: GenericClassEx.java uses or overrides a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
1 error

Answer 1

You need to pass an object of Student to the constructor, GenericClassEx(T data) . Instead of that, you are passing two arguments, "prince" and d to it.

Replace

GenericClassEx<Student> iobj= new GenericClassEx <Student> ("prince",d);

with

GenericClassEx<Student> iobj = new GenericClassEx<Student>(new Student("prince", d));

As a side note, the constructor, Float(double value) is deprecated since Java-9.

Replace

Float d = new Float(10);

with

Float d = Float.valueOf(10);