Can parent and child class in Java have same instance variable?

Question

Consider these classes:

class Parent {
 int a;
}

class Child extends Parent {
 int a; // error?
}

Should the declaration of a

Answer 1

It's called shadowing and may cause problems for developpers.

In your case :

Child child = new Child();
child.a = 1;
System.out.println(child.a);
System.out.println(((Parent)child).a);

would print

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