Install Java Runtime Environment (JRE) or Java Development Kit (JDK)
Open Command Prompt, Terminal, or PowerShell
Navigate to the folder containing the JAR file
Run `java -jar filename.jar`
Replace `filename.jar` with the actual JAR file name
If needed, use `java -jar path/to/filename.jar`
Ensure the JAR file is executable and has a valid manifest
On Windows, you can also double-click the JAR file if file associations are set
On Linux or macOS, use `chmod +x filename.jar` only if the JAR is designed to be executable
Use `java -version` to verify Java is installed
Use `jar tf filename.jar` to inspect the contents if needed