Advanced quizzes – Java inheritance

The following Java exercise(s) are designed for advanced level developers. If the level is too hard, then I recommend to select an easier one or you might consider reading my article about this topic, which offers a theoretical explanation including more exercises. Read More: Java Inheritance.

inheritance-red

Quiz 1: Inheritance, accessing methods and constructors of a super class.

What happens when the following program is compiled and run?

public class SuperB {

	protected int a = 2;
	protected int b = 3;

	public SuperB() {
		a += 1;
		b += 2;
		System.out.print("-b" + b);
	}
	public SuperB(int i) {
		this();
		b -= 1;
		System.out.print("-b" + a);
		a -= 1;
	}
	public int getB(){
		this.a += 2;
		this.b += 4;
		return b - a;
	}
}

public class SuperA extends SuperB {

	int a;
	int b = 1;

	public SuperA() {
		super(3);
		a += 7;
		b += 5;
	}
}

public class MySub extends SuperA {

	public MySub() {
		System.out.print("-b" + a);
		System.out.print("-b" + b);
		System.out.print("-b" + getB());
	}
	public static void main(String[] args){
		MySub mySub = new MySub();
	}
}

Select the correct answer.


Please, leave your questions, feedback and suggestions in the comments below!
SarMaroof.com offers a practical method to learn and improve your Java skills. It avoids unnecessary long boring theoretical explanations, but it uses many exercises and quizzes.


Sar Maroof is graduated from HBO Amsterdam "higher professional education". He is a professional computer programming teacher, gives master classes and publishes technical articles. His experience with developing software started from 2001 and he has worked as a software developer for several big as well as small companies and later as a freelancer. He is the author of Java quizmaster and Build a Java application in 7 days.

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1 Comment

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  1. That’s 2 clever by half and 2×2 clever 4 me. Thnska!

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