Beginner quizzes – Java Interfaces

The following Java exercise(s) are designed for beginner level programmers. If the level is too hard, then I recommend reading my article about this topic, which offers a theoretical explanation including more exercises. Read More: Java Interfaces

interface-green

Quiz 1: Easy Java Interface

What happens when the following program is compiled and run?

public interface MyInterface {

	int SMALL_NUMBER = 2;
	int NUMBER = 6;
	int getSum(int nr1, int nr2, int nr3);
}

public class MyClass implements MyInterface {

	public int getSum(int a, int b, int c){
		return NUMBER * a + b - SMALL_NUMBER / c;
	}
	public static void main(String[] args){
		MyClass mc = new MyClass();
		int x = mc.getSum(2,5,2);
		System.out.print(x);
	}
}

Select the correct answer.


Quiz 2: Implementing an interface in Java

What happens when the following program is compiled and run?

public interface MyInterface {

	int NUMBER = 4;
	String s = "x";
	void setMethod();
	void setMethod(String s, int n);
}

public class MyClass implements MyInterface {

	int NUMBER = 2;
	String s = "y";

	public void setMethod(){
		System.out.print("-" + MyInterface.s + NUMBER);
	}
	public void setMethod(String s, int n){
		System.out.print("-" + s + MyInterface.NUMBER);
	}
	public static void main(String[] args){

		MyClass mc = new MyClass();
		mc.setMethod();
		mc.setMethod("z",7);
	}
}

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” when he already had a bachelor of science degree in Physics. He is a SUN certified JSP as well as EJB. He has experience with Java since 2001 and worked for several big as well as small companies and later as a freelancer. The combination of his experiences and skills as a teacher and as a Java web developer inspired him to share his knowledge through writing books.

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