Because `core.jar` is an executable java archive, it is possible to start GroIMP just by (double-)clicking on the file in your system's file browser as you would do with a usual executable file. This requires a suitable setup of your file browser, see the documentation of the browser and your Java installation if it does not already work.

You can set up your desktop to show a menu entry for GroIMP. How this is done depends on your system. Usually your system provides a menu editor where you can create a new menu entry and specifiy the command to be executed when the entry is activated. Choose the command as you would do on command line.

The file `core.jar` in your installation directory of GroIMP's binary distribution is the entry-point for starting GroIMP. Running GroIMP from the command line is easy:

java -jar path/to/core.jar

Of course, `path/to/core.jar` has to be replaced by the actual path to the file `core.jar`. E.g., if, on a Unix system, the installation directory is `/usr/lib/groimp`, the command would be

java -jar /usr/lib/groimp/core.jar

or, on a Windows system with installation directory `C:\Program Files\GroIMP`,

java -Xverify:none -jar “C:\\Program Files\\GroIMP\\core.jar”

Alternatively, if you wish to start GroIMP from a batch file from your cmd console in Windows, you could write a file called groimp.bat (which you would place in your home directory, C:\\Users\\myself\\, where 'myself' is your user directory) with the following content:

cd “C:\Program Files\GroIMP 2.1.5”
“C:\Program Files\Java\jdk-22\bin\javaw.exe” -Xmx3000m -Xss20M -noverify -jar core.jar

where “C:\Program Files\Java\jdk-22\bin\javaw.exe” is an example of the placement of your javaw version, assuming we use jdk22.

See GroIMP interfaces for more details.

GroIMP can be run from different interfaces. By default, GroIMP use the “imp” interface which is its Graphical User Interface (GUI).

GroIMP can also be started headless, from CLI, or API.

To define which interface is used, when starting GroIMP you need to pass the parameter -a. E.g.

> java -jar core.jar -a api

More information can be found for using GroIMP headless, CLI, and API.