Beginner quizzes – Java language fundamentals

Written By Sar Maroof - Sarmaroof.com

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. .

Choose a level: Beginner Intermediate Advanced

Quiz 1: Java wrapper classes “Integer” objects

What happens when you try to compile and run the following program?

public class MyClass {

    public static void main(String[] args) {
        Integer integer1 = new Integer("5");
        Integer integer2 = new Integer("5");
        Object obj1 = (Object) integer1;
        Object obj2 = (Object) integer2;

        if (obj1.equals(obj2)) {
            System.out.print("e");
        } else {
            System.out.print("f");
        }
    }
}

Quiz 2: Java Strings

What happens when you try to compile and run the following program?

class MyClass {

	public static void main(String[] args){
		String str1 = new String("string");
		String str2 = new String("string");
		if(str1 == str2) {
			System.out.print("n");
		}else {
			System.out.print("o");
		}
		if(str1.equals(str2)) {
			System.out.print("p");
		}else {
			System.out.print("q");
		}
	}
}

Quiz 3: Using “String” method indexOf

What does the following code do?

public class MyClass {

	public void method(){
		String str = "abcde";
		System.out.print(str.indexOf("d"));
	}
	public static void main(String[] args){
		MyClass mc = new MyClass();
		mc.method();
	}
}

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.

Choose a level: Beginner Intermediate Advanced

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Sar Maroof is the author of two Java books namely, Java quizmaster for beginners and A guide to build a Java application.
Experience with developing web applications since 2001
Sun Certified JSP as well as EJB
CIW Certified Internet Webmaster
Applied Science in Physics HBO Amsterdam
As well as Bachellor Science in Physics.

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