As stated on the comments, that concept of application root directory generally don't apply to Ubuntu packages, but to compressed archives (.tar.gz or .zip, for example) that you can extract to somewhere you want. There the root directory may be the directory you extracted (if the compressed file contains a directory).
In your specific case, the application root seems to be in
/usr/share/dbeaver. You can try to place there the files but you will need root permission. Also it is not a very good solution, so check one of the following options first.
In your case, you seem to be trying to install this, and the manual driver installation should only be needed if you downloaded the
.zip version. From the website:
Note: Generally you don’t need to download this archive. It may be useful if you are going to use DBeaver in an environment without internet access.
So check if the application don't comes already with those drivers. If not check if it has not a functionality inside the application to install them.
Indeed the application allows you to install the drivers, but for some reason the installation always fails (on the .deb version, maybe because of no write permission). So you have two options:
Download the .zip version and uninstall the .deb version: after you download just extract the folder contained on that archive and place it wherever you want. The root directory of the application will be that directory so you just place there the needed .jar's. If it doesn't work try place them on the
You will have to specify the paths to the drivers on the application. Go to "Database" -> "Driver manager". There select the driver you want and press "Edit". You will see something asking you to install the driver. Press "OK".
It will then probably fail but press "Ignore". You will see the following screen:
delete the red item (by selecting it and pressing "Delete") and use "Add Folder" to specify the location where you extracted the JDBC drivers.
Hope it helps.