JDK provides several logical fonts but these have become very
static and difficult to update.
Some apps want to know the desktop font and have resorted
to code like this :

      WindowsLookAndFeel laf = new WindowsLookAndFeel();
      Font f = (Font)laf.getDefaults().get("Label.font");

which will not be accessible in JDK 9 due to encapsulation.

We could add an API that returns not a logical font as such
but a named physical font that is the font used by the current
desktop environment.
Desktops use multiple fonts so it should be the font that
is "typically" used, if not universally.