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


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.

Sar Maroof is a professional software development teacher, gives master classes and publishes technical articles. He is also an expert software developer and worked for several big as well as small companies and later as a freelancer.
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1 Comment

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

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