Make Launcher use my current GTK Look and Feel

What I expected to happen was launcher using my GTK+ 2/3 style (Greybird atm). What actually happened was default Swing window with awful default theme - "Metal"
Steps to Reproduce:
1. Put a variable into my ~/.bashrc:
export _JAVA_OPTIONS='-Dawt.useSystemAAFontSettings=on -Dswing.aatext=true -Dswing.defaultlaf=com.sun.java.swing.plaf.gtk.GTKLookAndFeel'
2. Put a setting string inside Swing config [$JAVA_HOME/jre/lib/swing.properties]:
swing.defaultlaf=com.sun.java.swing.plaf.gtk.GTKLookAndFeel
3. Launch game, see this - http://i1.5cm.ru/i/Q5ua.png. Relieve. Maybe it works!
4. See this - http://i1.5cm.ru/i/KU6k.png. Get depressed.