**Course Title:** Kotlin Programming: From Basics to Advanced Techniques **Section Title:** Interoperability with Java **Topic:** Integrate a Java library into a Kotlin project and demonstrate interoperability.(Lab topic) **Overview** Kotlin is designed to be fully interoperable with Java, making it seamless to integrate Java libraries into your Kotlin projects. In this lab, we will walk you through the steps to integrate a Java library into a Kotlin project and demonstrate how to take advantage of Kotlin's interoperability features. **Step 1: Choose a Java Library** For this lab, let's choose the Apache Commons Lang library, which provides a set of reusable Java utilities for tasks such as string manipulation, data structures, and more. Download the Apache Commons Lang JAR file from the official website: [https://commons.apache.org/proper/commons-lang/download_lang.cgi](https://commons.apache.org/proper/commons-lang/download_lang.cgi). **Step 2: Set up the Kotlin Project** Create a new Kotlin project in IntelliJ IDEA or Android Studio. Name the project "JavaInterop" and choose the "Kotlin" language. **Step 3: Add the Java Library to the Project** Add the downloaded Apache Commons Lang JAR file to the project's classpath. To do this: * Open the project structure dialog (File -> Project Structure). * Select "Modules" under the "Project Settings" section. * Click the "+" button to add a new dependency. * Choose "JARs or directories" and select the Apache Commons Lang JAR file. * Apply the changes and close the project structure dialog. **Step 4: Use the Java Library in Kotlin** Create a new Kotlin class, "JavaInterop.kt", and import the Apache Commons Lang library: ```kotlin import org.apache.commons.lang3.StringUtils fun main() { val originalString = "Hello, World!" val reversedString = StringUtils.reverse(originalString) println(reversedString) // prints "!dlroW ,olleH" } ``` In this example, we're using the `StringUtils.reverse()` method from the Apache Commons Lang library to reverse a string. **Step 5: Run the Application** Run the Kotlin application by clicking the "Run" button or pressing Shift+F10. **What to Expect** When you run the application, you should see the reversed string printed to the console. This demonstrates that we've successfully integrated the Java library into our Kotlin project and can use its functionality. **Practical Takeaways** * Kotlin's interoperability with Java allows you to easily integrate Java libraries into your Kotlin projects. * To add a Java library to a Kotlin project, download the JAR file and add it to the project's classpath. * Use Java classes and methods in Kotlin just like you would in Java, except you can take advantage of Kotlin's null-safety features. **Leave a Comment/Ask for Help** If you have any questions or issues during the lab, feel free to leave a comment below. We'll respond as soon as possible. Next topic: **Importance of testing in software development** in **Testing in Kotlin**.