Java Code Can't understand why it give the error?

Question

Here I make two classes A And prac2 and I just want to print the method from the both of class . But I got the error type of Class A is already defined . So I can't undestand why the error comes

package revision;


public class Prac2 extends A {
    public void m() {
        System.out.println("child");
    }
    
    public static void main(String[] args) {
        A obj1 = new Prac2() ;
        Prac2 obj2 = new Prac2() ;

        obj1.m();
        obj2.m();
        
    }

}

class A {
    public void m() {
        System.out.println("parent") ;
    }
}

Exception in thread "main" java.lang.NoSuchMethodError: 'void revision.A.m()'
    at revision.Prac2.main(Prac2.java:13)

The type A is already defined

Answer 1

your code seems to be ok with no exception, but it will print:

child

child

you extends Prac2 from A, that means A is the super class and if you want to get access to both methods, you should create instances from A:

class Prac2 extends A {
    public void m() {
        System.out.println("child");
    }

    public static void main(String[] args) {
        A obj1 = new A() ;
        A obj2 = new Prac2() ;

        obj1.m();
        obj2.m();

    }

}

class A {
    public void m() {
        System.out.println("parent") ;
    }
}

the output will be:

parent

child