Java inheritance fields [duplicate]

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First, see Hiding Fields (emphasis added)

Within a class, a field that has the same name as a field in the superclass hides the superclass’s field, even if their types are different

In other words, this isn’t “inheritance” since you’re actually hiding A‘s i behind B‘s i, and you are using a reference object of A, so you are getting its fields. If you did B b = new B(), you would see 20, as expected.

If you expect true overrides, try using methods. 

class A {
    public int get() { 
        return 10; 
    }
}

class B extends A {
    @Override 
    public int get() { 
        return 20; 
    }
}

See

A a = new B();
System.out.print(a.get()); // 20

If you really want to see both at once, see this example. 

class A {
    int i = 10;
}

class B extends A {
    int i = 20;

    @Override 
    public String toString() { 
        return String.format("super: %d; this: %d", super.i, this.i);
    }
}

And 

A a = new B();
System.out.print(a); // super: 10; this: 20

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