[Applet] Set java.library.path

[Dennis]

I wanna load an "*.dll" file in java, but I've read that I have to set an "java.library.path".

Now when I set the java.library.path in the applet self it won't use it.
When I use the appletviewer and set the java.library.path with the command:

appletviewer -J-Djava.security.policy=java.policy.applet -J-Djava.library.path=D:/java_libraries/j3d-1_5_2-windows-i586/bin index.html

The applet uses the java.library.path given in the startup command.

But I want to let it work in each browser.

java-code:

import java.awt.Color;
import java.awt.Graphics;

public class loader extends java.applet.Applet
{
	private String oldJLP;
	private String oldUD;
	
	private boolean error = false;
	private String message;
	
	public void init()
	{
		oldJLP=System.getProperty("java.library.path");
		oldUD=System.getProperty("user.dir");
		System.setProperty("java.library.path", "D:\\java_libraries\\j3d-1_5_2-windows-i586\\bin");
		System.setProperty("user.dir", "D:\\java_libraries\\j3d-1_5_2-windows-i586\\bin");
		try{
			System.loadLibrary("j3dcore-d3d");
			message = "j3dcore-d3d loaded";
		}catch(UnsatisfiedLinkError ex){
			error=true;
			message = ex.getMessage();
		}
	}
	
	public void paint(Graphics g)
	{
		g.drawString("old-JLP: " + oldJLP, 10, 10);
		g.drawString("new-JLP: " + System.getProperty("java.library.path"), 10, 30);
		g.drawString("old-UD: " + oldUD, 10, 50);
		g.drawString("new-UD: " + System.getProperty("user.dir"), 10, 70);
		if(error){
			g.setColor(Color.red);
			g.drawString("message: " + message, 10, 90);
		}else{
			g.setColor(Color.green);
			g.drawString("message: " + message, 10, 90);
		}
	}
}

html-code:

<applet code="loader.class" archive="loader.jar" width="1000" height="500"></applet>

java.policy.applet

/* AUTOMATICALLY GENERATED ON Tue Apr 16 17:20:59 EDT 2002*/
/* DO NOT EDIT */

grant {
  permission java.security.AllPermission;
};

I use the IDE Eclipse for create and test it at the most times.

The "j3dcore-d3d" is in "D:\java_libraries\j3d-1_5_2-windows-i586\bin".

Does someone know how I can set the java.library.path while the applet is running, tell me!

Thanks,
Dennis

[masijade]

The clients that want to use it will have to change their configurations.

[Dennis]

But I can sign the jar, so they have to accept the applet to run.

And I only want to set this changes temporary, only while the applet is running and only used by applet.

[masijade]

Doesn't matter. The library path needs to be set before the JVM is started in the browser. By the time it gets to the Applet, its too late. The clients will need to change their configuration.

[Dennis]

Okay,
But then it is quite strange that there is an function

System.setPropery("java.library.path", "...");

:P

Thank you for your help, I'll look for another way to let it work.

[masijade]

No, it's not quite strange. However, that particular system property is there for "informational" purposes only. That property list is nothing but a list of Strings from values that were set before the program started. There is no guarantee that any of those will be "looked at" and used dynamically. most of them will have been read and their value saved and won't be looked at again (by the JVM, but maybe by you).