namefilter is not called for file dialog on windows if it is set before creating file dialog's
peer.

Here is the test:

import java.awt.Frame;
import java.awt.FileDialog;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.File;
import java.io.FilenameFilter;

public class filter_test {
    private static volatile boolean accept_file = false;
    public static void main(String[] args) {
        Frame frame = new Frame("filter test");
        frame.setSize(100, 100);
        frame.addWindowListener(new WindowAdapter() {
                public void windowClosing(WindowEvent we) {
                    we.getWindow().dispose();
                }
            });
        frame.setVisible(true);
        FileDialog fd = new FileDialog(frame, "hello world", FileDialog.LOAD);
// fd.pack();
        fd.setFilenameFilter(new FilenameFilter() {
                public boolean accept(File dir, String name) {
                    accept_file = !accept_file;
                    System.out.println(Thread.currentThread() + " name = " + name + ", accept = " + accept_file);
                    return accept_file;
                }
            });
        fd.setDirectory("c:\\download");
        fd.setVisible(true);
    }
}

if uncomment fd.pack() then filter is called