Setting UI fontsize

Via the regular preferences you are able to control the fontsize for the editor window, but the rest of the UI might be somewhat clunky.

You can manually edit the ide.properties file located deep in $HOME/.sqldeveloper folder (path depends on version). Please note you might have several.

Comment in the Ide.FontSize and set the size.

Got the solution from an Ubuntu hint.

Found a Windows equivalent Googling.