Kotlin annotations for Java callers (@JvmStatic, @JvmField) - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to make the function callable as a static method from Java.

Kotlin

object Utils {
    @[1]
    fun greet() = "Hello from Kotlin"
}

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

AJvmField

BJvmOverloads

CJvmStatic

DJvmName

Attempts:

3 left

💡 Hint

Common Mistakes

Using @JvmField instead of @JvmStatic for functions.

The @JvmStatic annotation makes the function callable as a static method from Java.

2fill in blank

medium

Complete the code to expose the property as a public field in Java.

Kotlin

class Config {
    @[1]
    val version = "1.0"
}

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

AJvmField

BJvmName

CJvmStatic

DJvmOverloads

Attempts:

3 left

💡 Hint

Common Mistakes

Using @JvmStatic on properties instead of @JvmField.

The @JvmField annotation exposes the Kotlin property as a public field in Java, without getter/setter methods.

3fill in blank

hard

Fix the error by choosing the correct annotation to allow Java static access to the companion object's function.

Kotlin

class Helper {
    companion object {
        @[1]
        fun help() = "Helping"
    }
}

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

AJvmStatic

BJvmSynthetic

CJvmName

DJvmField

Attempts:

3 left

💡 Hint

Common Mistakes

Using @JvmField on functions inside companion objects.

Inside companion objects, @JvmStatic allows calling the function as a static method from Java.

4fill in blank

hard

Fill both blanks to expose a property as a public static field accessible from Java.

Kotlin

class Constants {
    companion object {
        @[1]
        @[2]
        val MAX_COUNT = 100
    }
}

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

AJvmField

BJvmStatic

CJvmName

DJvmSynthetic

Attempts:

3 left

💡 Hint

Common Mistakes

Using only one annotation, causing no static field in Java.

Using both @JvmField and @JvmStatic on a companion object property exposes it as a static field in Java.

5fill in blank

hard

Fill all three blanks to create a Kotlin object with a static function and a public field accessible from Java.

Kotlin

object Logger {
    @[1]
    fun log(message: String) = println(message)

    @[2]
    val DEFAULT_TAG = "APP"
}

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

AJvmStatic

BJvmField

CJvmName

DJvmSynthetic

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing @JvmField and @JvmStatic usage on functions and properties.

@JvmStatic makes the function static for Java callers. @JvmField exposes the property as a public field.