How to run jar files in Linux

Prerequisites for running JAR files

Running JAR files on a Linux system requires installing the Java Runtime Environment (JRE), which is the basic component required to execute Java applications, including Java Virtual Machine (JVM), core class libraries, etc.

Many mainstream Linux distributions, such as Ubuntu, Debian, Fedora, openSUSE, etc., provide software libraries for JRE packages to facilitate user installation. The steps to install JRE on popular distributions are detailed below.

After setting up the JRE, you can choose to use the command line terminal or the graphical user interface to start the JAR file according to your personal preference. Your choice may depend on your familiarity with Linux shells and personal preference.

Installing Java Runtime Environment on Linux

Here are step-by-step instructions for installing the JRE on some of the most widely used Linux distributions:

Installing JRE on Ubuntu and Debian

To set up the JRE on Ubuntu or a related Debian-based distribution (such as Linux Mint), perform the following procedure using the apt package manager:

sudo apt install default-jre

Verify that the JRE is installed correctly by checking its version:

java -version

This will output details about the installed JRE and confirm that it is set up correctly.

Installing JRE on openSUSE

For openSUSE Leap/Tumbleweed installation, the JRE is set up as follows:

sudo zypper install java-11-openjdk

Confirm that the appropriate JRE is now active:

java -version

Installing JRE on other Linux distributions

For other distributions, search their package repositories for available JRE/JDK packages. Some options are:

• On MX Linux, use:

sudo apt install default-jre

sudo apt install default-jre

• On Kali Linux, use:

sudo yum instal

• On CentOS, use:

l java-11-openjdk

• On AlmaLinux, use:

sudo dnf install java-latest-openjdk

• On RHEL, enable the EPEL repository and use:

sudo yum install java-11-openjdk

This covers the installation process for most common Linux distributions. Now we can move on to actually running the JAR file.

Run the JAR file through the command line

After installing the JRE, you can use the java command to execute the JAR file from the terminal. The following is the basic syntax:

java -jar 

For example, start a file named app. Jar uses:

java -jar app.jar

This file requires executable permissions to work properly. To avoid permission errors, set permissions before running the JAR:

chmod +x app.jar
java -jar app.jar

Some additional options you can pass to java -jar:

• To set the maximum Java heap size (2GB in this example):

java -jar -Xmx2G app.jar

• To view JAR verification warnings:

java -jar -Xverify:none app.jar

• To disable Java caching when launching a JAR:

java -jar -Xint app.jar

• To run a JAR file silently in the background instead of spawning a new window:

java -jar app.jar &

This covers the key things you need to know about launching a JAR file from the command line terminal on Linux.

Run the JAR file through the graphical user interface

If you prefer to click on JAR files rather than use the terminal, the Linux desktop environment also provides a graphical way to execute them. Here are some options:

File Manager Context Menu

Most Linux file managers, such as Nautilus (GNOME Files), Dolphin, Thunar, etc., automatically register the .jar file type to allow it to be executed from the right-click context menu.

Simply right-click on the JAR file, hover over "Open with" and select "Java" or any installed JRE from the menu. This will start the JAR application.

Desktop Launcher

Another method is to use a menu launcher, which allows you to create shortcuts to run JAR files, similar to Windows .exe or Linux .desktop files. For example, in KDE Plasma you can:

Right click on the JAR file and create launcher.

If you want terminal output, check the "Run in Terminal" option.

Launch the JAR by double-clicking the launcher icon.

GNOME, Xfce and other desktops have similar functionality to generate launchers.

Custom file association

You can also manually associate .jars files opened with JRE when double-clicked.

On GNOME, use the "Other Applications" option in "Preferences" - "> File Associations" to .jar files always start using the java -jar command .

So, in summary, all major Linux GUIs include methods to graphically execute JAR files without using a terminal.

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