How to find font size defined in user environment

Hi experts.

I am writing a stand-alone desktop application on Linux. On Linux, a user can change font style/font size etc from the gui easily. So, I would like to know about the font setting that a user choose to display. I am using UIManager to get a look and feel. By knowing the font size defined by a user, I would like to scale GUI components like size of text field, drop down menu etc.

Is there any way to find out the user setting (font size) on their environment ?
I checked system property and tookkit, but I could not find anything useful.

Thanks,
yasushi