Java platform and JVM overview - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to print "Hello, JVM!" in Java.

Java

public class Main {
    public static void main(String[] args) {
        System.[1]("Hello, JVM!");
    }
}

Drag options to blanks, or click blank then click option'

Aprintln

Becho

Cwrite

Dprint

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'print' which does not add a new line.

Using 'write' or 'echo' which are not valid methods here.

The println method prints the text and moves to a new line, which is the standard way to output in Java.

2fill in blank

medium

Complete the code to declare a variable of type int with value 10.

Java

public class Main {
    public static void main(String[] args) {
        [1] number = 10;
    }
}

Drag options to blanks, or click blank then click option'

Adouble

Bint

CString

Dboolean

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'String' which is for text.

Using 'double' which is for decimal numbers.

The int type is used to store whole numbers like 10.

3fill in blank

hard

Fix the error in the code to correctly create a new String object.

Java

public class Main {
    public static void main(String[] args) {
        String text = new [1]("Java");
    }
}

Drag options to blanks, or click blank then click option'

Astring

BStringBuilder

CString

DText

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase 'string' which is not a class in Java.

Using 'StringBuilder' which is a different class.

The class name String must be capitalized exactly to create a new String object.

4fill in blank

hard

Fill both blanks to create a simple for loop that prints numbers 1 to 5.

Java

public class Main {
    public static void main(String[] args) {
        for (int i = [1]; i [2] 5; i++) {
            System.out.println(i);
        }
    }
}

Drag options to blanks, or click blank then click option'

A1

B0

C<=

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Starting from 0 which prints 0 to 4.

Using '<' which excludes 5.

The loop starts at 1 and continues while i is less than or equal to 5 to print numbers 1 through 5.

5fill in blank

hard

Fill all three blanks to create a method that returns the square of a number.

Java

public class Main {
    public static int [1](int [2]) {
        return [2] [3] [2];
    }
}

Drag options to blanks, or click blank then click option'

Asquare

Bnum

C*

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+' instead of '*' which adds instead of multiplies.

Using unclear variable names.

The method named 'square' takes an integer 'num' and returns its multiplication by itself.