How can I properly call NSOpenPanel from a JNI method to run on the proper thread?

I can get my JNI class to only partially execute due to my unfamiliarity with Objective-C and JNF. What I've tried so far is as follows:

Here's Open.java

import java.awt.event.*;import javax.swing.*;public class Open extends JFrame {   public Open () {      getContentPane().add(new JButton(new AbstractAction() {         public void actionPerformed (ActionEvent e) {            try {               NativeOpenFileDialog.run();            } catch (Throwable ex) {               System.err.println(ex.getMessage());            }         }      }));      pack();      setVisible(true);   }   public static void main(String[] args) {      SwingUtilities.invokeLater(new Runnable() {         public void run() { new Open(); }      });   }}

Here's NativeOpenFileDialog.java

import javax.swing.*;public class NativeOpenFileDialog {   static {       System.loadLibrary("natopndlg");   };   public static native void run ();   public static void main (String[] args) {      SwingUtilities.invokeLater(new Runnable() {         public void run() { NativeOpenFileDialog.run(); }      });   }}

Here's NativeOpenFileDialog.m

#import <Cocoa/Cocoa.h>#include <jni.h>#include "NativeOpenFileDialog.h"JNIEXPORT void JNICALL Java_NativeOpenFileDialog_run (JNIEnv *thisEnv, jclass jcls) {    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];    NSOpenPanel *panel = [NSOpenPanel openPanel];    [panel setCanChooseFiles:YES];    [panel setCanChooseDirectories:YES];    [panel setAllowsMultipleSelection:YES];    if ([panel runModal] != NSModalResponseOK)        NSLog(@"User did not press OK");    [pool release];}

And here's the makefile (I'm using Xcode 15.2):

SDK = /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdkOpen.class: Open.java NativeOpenFileDialog.java NativeOpenFileDialog.m    javac -h . NativeOpenFileDialog.java    javac Open.java    gcc -dynamiclib -o libnatopndlg.dylib -framework Cocoa -isysroot $(SDK) -I $(JAVA_HOME)/include -I $(JAVA_HOME)/include/darwin -fobjc-exceptions -std=c99 NativeOpenFileDialog.m

$ java Open

That command raises this exception when the button is clicked:

NSInternalInconsistencyException', reason: 'NSWindow should only be instantiated on the main thread!

Which is understandable knowing that the panel is supposed to be opened on the UI thread.