Classes and Objects Interview Questions

    Question 1: JAVA OOPS - Class and Object Creation

    Which of the following correctly creates an object of class Car?

    class Car {}

    Question 2: JAVA OOPS - Accessing Object Members

    What will be the output of the following code?

    class Test {
    int x = 10;
}
public class Main {
    public static void main(String[] args) {
        Test t = new Test();
        System.out.println(t.x);
    }
}

    Question 3: JAVA OOPS - Default Constructor

    What does Java provide if no constructor is defined in a class?

    class Person {}

    Question 4: JAVA OOPS - Object Reference Assignment

    What will be printed?

    class Demo {
    int a = 5;
}
public class Main {
    public static void main(String[] args) {
        Demo d1 = new Demo();
        Demo d2 = d1;
        d2.a = 10;
        System.out.println(d1.a);
    }
}

    Question 5: JAVA OOPS - Object Creation Syntax

    Which statement is invalid?

    class Car {}

    Question 6: JAVA OOPS - Class Member Access

    What will be the output?

    class A {
    int x = 10;
}
class B {
    int y = 20;
}
public class Main {
    public static void main(String[] args) {
        A a = new A();
        B b = new B();
        System.out.println(a.x + b.y);
    }
}

    Question 7: JAVA OOPS - Multiple Objects

    What does the following code demonstrate?

    class Counter {
    int count = 0;
}
public class Main {
    public static void main(String[] args) {
        Counter c1 = new Counter();
        Counter c2 = new Counter();
        c1.count++;
        System.out.println(c2.count);
    }
}

    Question 8: JAVA OOPS - Object Null Reference

    What happens if we access a method via a null object?

    class Demo {
    void show() { System.out.println("Hello"); }
}
public class Main {
    public static void main(String[] args) {
        Demo d = null;
        d.show();
    }
}

    Question 9: JAVA OOPS - Object Initialization

    Which is true about objects in Java?

    Question 10: JAVA OOPS - this Keyword Usage

    What does the this keyword represent in Java?

    class Test {
    int x;
    Test(int x) { this.x = x; }
}