These settings should already be enabled by default. If you believe they are not, try running the application using java -jar masterpassword-gui.jar -Dawt.useSystemAAFontSettings=on -Dswing.aatext=true to see if this makes any difference.
In my tests, fonts look decent. Can you attach screenshots of your issues / share your platform details?
Running it with the given parameters is not making a difference. Maybe it is already activated, but the fonts are pixelated.
Maybe it is font-dependent, some look better than others.
You can see the letters y or w for example, the home folder and the link in the bottom.
I'm not comfortable overriding system defaults. There may be a very good reason why AA is not enabled by default on Linux. And even if there isn't, that isn't necessarily true for all other platforms ever.