Calling Kotlin from Java - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to call a Kotlin function from Java.

Kotlin

KotlinClass.[1]();

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

Astart

Bmain

Crun

Dgreet

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong method name like 'main' or 'run'.

The Kotlin function greet is called from Java using the class name and method name.

2fill in blank

medium

Complete the Java code to create an instance of a Kotlin class.

Kotlin

KotlinClass [1] = new KotlinClass();

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Aobj

Binstance

CkotlinObj

DkotlinInstance

Attempts:

3 left

💡 Hint

Common Mistakes

Using invalid variable names or keywords.

We create a new instance of the Kotlin class and assign it to the variable named instance.

3fill in blank

hard

Fix the error in calling a Kotlin function with parameters from Java.

Kotlin

int result = kotlinObj.[1](5, 3);

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AaddNumbers

Badd

Csum

Dcalculate

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect function names like 'add' or 'sum'.

The Kotlin function is named addNumbers, so calling it with the correct name fixes the error.

4fill in blank

hard

Fill both blanks to call a Kotlin property getter from Java.

Kotlin

String name = kotlinObj.[1]();
System.out.println(name [2] " is called from Java.");

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

AgetName

B+

C-

DsetName

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'setName' instead of 'getName'.

Using '-' instead of '+' for concatenation.

The Kotlin property name is accessed via its getter getName() in Java. The plus sign + concatenates strings.

5fill in blank

hard

Fill all three blanks to call a Kotlin companion object function from Java.

Kotlin

int max = KotlinClass.[1].[2]([3]);

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ACompanion

BmaxOf

C10, 20

Dcompanion

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase 'companion' instead of 'Companion'.

Passing arguments incorrectly.

In Java, Kotlin companion object functions are accessed via the Companion object. The function maxOf is called with arguments 10, 20.