Java OOPs Concepts Test 2

    Question 1: JAVA OOPS - Default Constructor

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

    class Person {}

    Question 2: JAVA OOPS - Constructor Overloading

    What will be printed?

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

    Question 3: JAVA OOPS - Hierarchical Inheritance

    Which is true about hierarchical inheritance?

    Question 4: JAVA OOPS - Runtime Polymorphism

    What will be printed?

    class A { void show() { System.out.println("A"); } }
class B extends A { void show() { System.out.println("B"); } }
public class Main {
    public static void main(String[] args) {
        A obj = new B();
        obj.show();
    }
}

    Question 5: JAVA OOPS - Abstract Class Constructor

    Which statement is true about constructors in abstract classes?

    Question 6: JAVA OOPS - Access Modifier Importance

    Why are private access modifiers important in encapsulation?

    Question 7: JAVA OOPS - Multiple Interface Implementation

    Which of the following is correct?

    interface A { void showA(); }
interface B { void showB(); }
class C implements A, B {
    public void showA() { System.out.println("A"); }
    public void showB() { System.out.println("B"); }
}

    Question 8: JAVA OOPS - Creating a Package

    Which of the following correctly creates a package?

    package com.example;
public class Test {}

    Question 9: JAVA OOPS - Final Method

    Which of the following statements about final methods is correct?

    Question 10: JAVA OOPS - Overriding Basics

    Which statement about method overriding is true?

    Question 11: 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 12: JAVA OOPS - Constructor Without `void`

    Which is true about constructors?

    Question 13: JAVA OOPS - Method Overriding in Inheritance

    What will be printed?

    class A { void show() { System.out.println("Parent"); } }
class B extends A { void show() { System.out.println("Child"); } }
public class Main {
    public static void main(String[] args) {
        A a = new B();
        a.show();
    }
}

    Question 14: JAVA OOPS - Polymorphism with Parameters

    Which of the following is true about polymorphism in Java?

    Question 15: JAVA OOPS - Multiple Abstract Classes

    Which statement is correct?

    Question 16: JAVA OOPS - Read-only Property

    How can you make a class property read-only?

    class Demo {
    private int value;
    public int getValue() { return value; }
}

    Question 17: JAVA OOPS - Default Methods in Interface

    Which is true about default methods in Java interfaces?

    Question 18: JAVA OOPS - Importing a Package

    How do you import the `Test` class from `com.example` package?

    Question 19: JAVA OOPS - Final Method Example

    What will happen when compiling the following code?

    class A {
    final void show() { System.out.println("A"); }
}
class B extends A {
    // void show() { System.out.println("B"); }
}

    Question 20: JAVA OOPS - Overriding Example

    What will be printed?

    class A { void show() { System.out.println("A"); } }
class B extends A { void show() { System.out.println("B"); } }
public class Main {
    public static void main(String[] args) {
        A obj = new B();
        obj.show();
    }
}