How to Use the Kotlin Command (with Examples)
Kotlin is a modern, versatile, and powerful programming language that runs on the Java Virtual Machine (JVM). It’s designed to integrate seamlessly with Java, offering a more concise syntax and a host of additional features. The kotlin command is a tool used to launch Kotlin applications. It provides various functionalities such as running JAR files and displaying version information for Kotlin and the JVM.
Use Case 1: Running a Jar File
Code:
kotlin filename.jar
Motivation:
Running a JAR (Java ARchive) file is one of the most common tasks for Java and Kotlin developers. Once you have compiled your Kotlin application into a JAR file, executing it is essential for testing your code and deploying the application. The kotlin command directly supports this functionality, allowing you to launch any Kotlin application encapsulated in a JAR file with ease.
Explanation:
kotlin: This is the command to use the Kotlin application launcher. It serves as an entry point to the Kotlin runtime on the JVM.filename.jar: This parameter specifies the file name of the JAR you wish to run. The file must be a compiled Kotlin application, packaged as a JAR. The.jarextension is required to recognize the file type.
Example Output:
Hello, World!
The output will depend on the logic written within the Kotlin application contained inside the JAR file. For example, if the application is designed to print “Hello, World!” to the console, this will be the resulting output upon executing the command.
Use Case 2: Displaying Kotlin and JVM Version
Code:
kotlin -version
Motivation:
Knowing the version of Kotlin and the JVM that you are using is crucial for maintaining compatibility with your project requirements. It helps in ensuring that your code utilizes the correct features of the language and avoids incompatibilities caused by version mismatches. This information is particularly useful for debugging and when seeking help from development communities, as it provides context about your system environment.
Explanation:
kotlin: This is the foundational command to access Kotlin’s features and tools.-version: This argument requests the version information of both Kotlin and the Java Virtual Machine (JVM) on which Kotlin is running. The single dash-signifies a short-form option or flag in the command-line interface.
Example Output:
Kotlin version 1.5.31-release-546 (JRE 11.0.12+7-LTS)
The output presents the Kotlin version followed by the version of the Java Runtime Environment (JRE). This information empowers developers to verify their development environment’s setup and ensure compatibility across various build processes and third-party libraries.
Conclusion:
The kotlin command serves as an integral tool for developers working within the Kotlin ecosystem. Its ability to execute JAR files facilitates the seamless execution of compiled Kotlin applications, while providing version details assists developers in maintaining environment consistency. Mastering these simple yet crucial functionalities can expedite development workflows and aid in troubleshooting.
