Intermediate quizzes – Java interfaces

The following Java exercise(s) are designed for intermediate level programmers. 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 Interfaces

interface-blue

Quiz 1: Implementing interfaces in Java

What happens when the following program is compiled and run?

public interface InterfaceB {

	int NUMBER = 1;
	int method();
}

public interface InterfaceA extends InterfaceB {

	int NUMBER = 4;
}

public class MyClass implements InterfaceA {

	int NUMBER = 2;

	public int method(){
		return NUMBER;
	}
	public static void main(String[] args){
		InterfaceA iA = new MyClass();
		InterfaceB iB = new MyClass();
		MyClass mc = new MyClass();
		System.out.print("-v" + mc.NUMBER + "-m" + iB.method());
		System.out.print("-v" + iA.NUMBER + "-m" + iA.method());
		System.out.print("-v" + iB.NUMBER + "-m" + iB.method());
	}
}

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. I’m so glad I found my solituon online.

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