A jar is java package - a zip-compressed archive - including the code for a java application.
The jar requires at least JRE (Java Runtime Environment) - some requires the full JDK (Java Development Kit). A JDK contains the corresponding JRE.
If in doubt of the actual requirements of the application - install the JDK.
To install the latest JRE
sudo pacman -Syu jre-openjdk
Or the complete environment
sudo pacman -Syu jdk-openjdk
To run the application contained in the jar
java -jar java-app.jar
If you want to launch the program from your menu or the terminal - create a script and a launcher as follows.
Create the bin folder
Move the jar to the bin folder
Assuming it is in Downloads
mv ~/Downloads/java-app.jar ~/.local/bin
Create the script
Open your favorite text editor with a new file and save it as ~/.local/bin/java-app with below content - the "$@" ensures that any arguments to the script is passed on to the java-app.jar file
#!/bin/sh java -jar ~/.local/bin/java-app.jar "$@"
Make the script executable
chmod +x ~/.local/bin/java-app
Create the application folder
mkdir -p ~/.local/share/applications
Create the desktop launcher
Use the text editor to create a new file and save it as ~/.local/share/applications/java-app.desktop with below content
[Desktop Entry] Encoding=UTF-8 Name=Some Java App Comment=Run the java-app.jar program GenericName=Some Java App Exec=~/.local/bin/java-app Terminal=false Type=Application Icon=java-app-icon Categories=Application; StartupWMClass=java-app StartupNotify=true
You are now be able to run Some Java App by providing the script name and any arguments for the java-app.jar and you can find it in the system's menu tree.