How to Access same name Variable Different Class Variable in Main Method in java

Question

Accessing Same Name Data Members In Main Method Using obj Object not creating object in Class A and Class B.

class A {
  int i = 10;
}
class B extends A {
 int i = 20;
}
class C extends B {
  int i = 30;
}
public class Main {
  public static void main (String[] args)   {
    C obj = new C ();
    System.out.println (obj.i);
    //How to access Class A variable
    //How to access Class B Variable
  }
}

Print Class A Variable Print Class B Variable Without Creating Object of Class A and Class B.

Answer 1

System.out.println (((A) obj).i); and System.out.println (((B) obj).i); respectively. If they were protected fields, they would be inherited. As is, they are hidden ( shadowed ) package-private fields.

Since you've now mentioned that you cannot use a simple cast, the next best option (I can think of) is reflection . You can iterate the Field (s), find the field named i , make it accessible and then print it (and the class name). For example,

try {
    Class<?>[] classes = { A.class, B.class, C.class };
    for (Class<?> cls : classes) {
        for (Field f : cls.getDeclaredFields()) {
            if (f.getName().equals("i")) {
                f.setAccessible(true);
                System.out.printf("%s %s%n", cls.getSimpleName(), f.get(obj));
            }
        }
    }
} catch (IllegalArgumentException | IllegalAccessException | SecurityException e) {
    e.printStackTrace();
}

Outputs

A 10
B 20
C 30

Answer 2

Use the Reflection. You can get the super class and get the i value. This approach don't use the typeCasting, create object and statie member. I think it will help you.

class A {
    int i = 10;
}
class B extends A {
    int i = 20;
}
class C extends B {
    int i = 30;
}
public class Main {
    public static void main (String[] args)   {
        try {
            C obj = new C();
            System.out.println(obj.i);
            // get the Class B
            Class b = obj.getClass().getSuperclass();
            System.out.println(b.getDeclaredField("i").getInt(obj));
            // get the Class A
            Class a = b.getSuperclass();
            System.out.println(a.getDeclaredField("i").getInt(obj));
        } catch (Exception e) {
            // ignore
        }

        // Output
        // 30
        // 20
        // 10
    }
}