Kotlin Calling Kotlin code from Java

Kotlin is a versatile programming language that can be used for Android development, server-side programming, and more. Sometimes, you may need to call Kotlin code from Java. In this tutorial, we will learn how to call Kotlin code from Java.

Syntax

To call Kotlin code from Java, you need to follow the steps below:

1. Create a Kotlin class or function.
2. Add the @JvmStatic annotation to the Kotlin function or companion object.
3. Compile the Kotlin code.
4. Create a Java class and import the Kotlin package.
5. Call the Kotlin function or companion object using the Java class.

Example

Let's say you have a Kotlin function that calculates the sum of two numbers:

class Calculator {
    companion object {
        @JvmStatic
        fun sum(a: Int, b: Int): Int {
            return a + b
        }
    }
}

To call this function from Java, you can create a Java class and import the Calculator class:

import com.example.Calculator;

public class Main {
    public static void main(String[] args) {
        int result = Calculator.Companion.sum(2, 3);
        System.out.println("Sum of 2 and 3 is: " + result);
    }
}

Output

When you run the Java class, you should see the output message printed on the console:

Sum of 2 and 3 is: 5

Explanation

To call Kotlin code from Java, you need to add the @JvmStatic annotation to the Kotlin function or companion object. This tells the Kotlin compiler to generate static Java methods for the function or companion object.

In the Java code, you can then call the function or companion object using the Kotlin class name and the Companion object.

Use

Calling Kotlin code from Java can be useful when you have legacy code in Java that needs to interact with Kotlin code. Additionally, it allows you to use the power of Kotlin in your Java projects.

Important Points

• Make sure to add the @JvmStatic annotation to the Kotlin function or companion object that you want to call from Java.
• When calling the Kotlin function or companion object from Java, use the Kotlin class name and the Companion object.
• Kotlin and Java code can coexist in the same project and can interact with each other seamlessly.

Summary

In this tutorial, we learned how to call Kotlin code from Java. We covered the syntax, example, output, explanation, use, important points, and summary of calling Kotlin code from Java. With this knowledge, you can now integrate Kotlin code into your Java projects and take advantage of its powerful features.