Why is the output different in the two cases?

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慢半拍i
慢半拍i 2021-01-22 06:10

Why is the output different in the below case even when, the variable has been overridden?

public class A {
    int a = 500;

    void get() {
        System.out         


        
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  • 2021-01-22 06:26

    No the variable is not overridden. ob.a print the a variable of B class. ob.get() searches for the get method in B class.when it does not gets there it then searches the parent class and executes it.

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  • 2021-01-22 06:35

    When doing ob.a, you get the variable int a from your ob object, which is object of the class B.

    However, when you do ob.get();, you are calling the get()-method from class A, because there is no get() in B, which - as you wrote - uses this.a, which would be the int a of class A in that case.

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  • 2021-01-22 06:36

    There is no such thing as overridden variables. B actually has two instance variables named a: one it declares and another it inherits. See this:

    B ob = new B();
    System.out.println("B.a is " + ob.a);
    System.out.println("A.a is " + ((A)ob).a);
    

    Inside a B's instance method you can write super.a or ((A)this).a to access the parent's variable.

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