How To Make a .jar File Executable in Ubuntu with OpenJDK

In this article, we will delve into the process of making a .jar file executable in Ubuntu using OpenJDK. We will cover three different methods: using the command line, using the graphical user interface (GUI), and creating a launcher. By the end of this guide, you should be able to execute .jar files with ease in your Ubuntu system.

Prerequisites

Before we begin, ensure that you have OpenJDK installed on your Ubuntu system. If not, you can install it using the following command:

sudo apt-get install openjdk-8-jdk

This command uses the apt-get package handling utility to install the OpenJDK 8 JDK. The sudo command is used to execute the command with administrative privileges.

Method 1: Using the Command Line

The command line is a powerful tool that can be used to change the permissions of files. Here’s how to make your .jar file executable using the command line:

1. Open a Terminal: You can do this by pressing Ctrl+Alt+T or searching for Terminal in your system’s application launcher.
2. Navigate to the Directory: Use the cd command to navigate to the directory where your .jar file is located. For instance, if your file is in the Downloads folder, you would use:

   cd ~/Downloads

3. Change File Permissions: Use the chmod command to make the .jar file executable. The syntax is as follows:

   chmod +x yourfile.jar

   In this command, chmod changes the permissions of files. The +x option adds the execute permission to the file.
4. Run the .jar File: Now, you can run the .jar file by executing the following command:

   java -jar yourfile.jar

   The java -jar command tells the system to use Java to execute the .jar file.

Method 2: Using the GUI

If you prefer using the graphical interface, follow these steps:

1. Open File Properties: Right-click on the .jar file and select “Properties”.
2. Change Permissions: Navigate to the “Permissions” tab and check the box that says “Allow executing file as a program”.
3. Run the .jar File: Close the properties window. You should now be able to double-click the .jar file to run it.

Method 3: Creating a Launcher

Creating a launcher can be a handy way to run .jar files. Here’s how to do it:

1. Create a New File: Open a text editor and create a new file.
2. Add Launcher Information: Add the following lines to the file:

   [Desktop Entry]
   Type=Application
   Name=Your Application Name
   Icon=/path/to/your/icon.png
   Exec=java -jar /path/to/your/file.jar
   Categories=Application;Java
   Terminal=false

   Replace “Your Application Name” with the desired name for your application. Replace “/path/to/your/icon.png” with the path to an icon image for your application (optional). Replace “/path/to/your/file.jar” with the actual path to your .jar file.
3. Save the File: Save the file with a “.desktop” extension, for example, “yourapplication.desktop”.
4. Move the .desktop File: Use the mv command to move the .desktop file to the ~/.local/share/applications directory.

   mv yourapplication.desktop ~/.local/share/applications

   The mv command moves files or directories from one place to another.
5. Run the .jar File: You should now be able to find your application in the application launcher and run it from there.

Conclusion

In this article, we have covered three different ways to make a .jar file executable in Ubuntu using OpenJDK: using the command line, using the GUI, and creating a launcher. Choose the method that best suits your needs and comfort level. Happy coding!