Tested with 7u10 b17 on Mac OS X 10.8

Download and install JRE DMG file.

Open http://docs.oracle.com/javase/tutorialJWS/uiswing/components/ex6/JWSFileChooserDemo.jnlp from safari. In the File chooser dialog, file with Chinese name is not displayed in the list.

Open the same jnlp file with javaws in command line, the file with Chinese name is displayed in the list.

Attached screenshots:
jnlpcommand: open the jnlp with javaws in command line, file with chinese name is in the list on file chooser dialog.
jnlpsafari: open the jnlp by clicking the button on the webpage in safari. Same JRE, but file with chinese name is not in the list on file chooser dialog.