Constructors Interview Questions Mock Test

Question 1: JAVA OOPS - Default Constructor

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

class Person {}

Question 2: JAVA OOPS - Parameterized Constructor

Which statement correctly creates a parameterized constructor object?

class Car {
    String model;
    Car(String m) { model = m; }
}

Question 3: 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 4: JAVA OOPS - Constructor Without `void`

Which is true about constructors?

Question 5: JAVA OOPS - `this()` Keyword in Constructor

What will the following code print?

class Test {
    Test() { System.out.println("Default"); }
    Test(int x) { this(); System.out.println(x); }
}
public class Main {
    public static void main(String[] args) {
        Test t = new Test(5);
    }
}

Question 6: JAVA OOPS - Constructor Chaining

Which concept is demonstrated here?

class Demo {
    Demo() { System.out.println("A"); }
    Demo(int x) { this(); System.out.println("B"); }
}

Question 7: JAVA OOPS - Object Initialization

Which is true about objects in Java?

Question 8: JAVA OOPS - Private Constructor

What is true about a private constructor?

class Demo {
    private Demo() {}
}

Question 9: JAVA OOPS - Constructor in Inheritance

What will be printed?

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

Question 10: JAVA OOPS - No-argument Constructor with Parameters

Will this code compile?

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