UnsatisfiedLinkError using Java Webstart with custom classloader

Andi <andreas.schneider@skillworks.de>
Mon, 17 Mar 2008 03:42:42 -0700 (PDT)

I have a big problem to get my Application running on java webstart. I
have a custom classloader which will be used for some classes. Also I
need to load a dll which will be used by a native interface.

Here is my application entry point:

public class ApplicationStarter
    public static void main(String[] args)
            CustomClassLoader classLoader = new
new Class[] { String[].class })
                    .invoke(null, new Object[] { args });
        catch (Exception e)

That all the classloading my classloader will be used I am calling the
real applcation per reflection loaded by my classloader.

Here the application I start:

public class Application
    public static void main(String[] args)
            NativeInterface nativeInterface = new NativeInterface();
            System.out.println("Native call result :" +
        catch (Throwable t)

Here my Classloader:

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;

public class CustomClassLoader extends ClassLoader

    private HashMap<String, Class<?>> loadedClasses = new
HashMap<String, Class<?>>();

    public CustomClassLoader(ClassLoader parent)

    public Class<?> customLoadClass(String name) throws
        System.out.println("Custom loading of class " + name);
        Class<?> clazz = this.loadedClasses.get(name);
        if(clazz == null)
                String classFilename = name.replace('.', '/') +

                InputStream inputStream =
                if(inputStream == null)
                    throw new ClassNotFoundException(name);

                ByteArrayOutputStream baout = new
                byte[] b = new byte[2048];
                int byteCount;
                while((byteCount = inputStream.read(b, 0, 2048)) !=
                    baout.write(b, 0, byteCount);
                byte[] buffer = baout.toByteArray();

                clazz = defineClass(name, buffer, 0, buffer.length);
                this.loadedClasses.put(name, clazz);

            catch (IOException e)
                throw new ClassNotFoundException(name, e);

        return clazz;

    public Class<?> loadClass(String name) throws
        Class<?> clazz;
            clazz = customLoadClass(name);
            clazz = super.loadClass(name);
        return clazz;

    public String toString()
        return getClass().getName();

That works perfect when I have a normal client application but it
doesn't when I use Java Webstart.

Here my jnlp:

<?xml version="1.0" encoding="utf-8"?>
<!-- JNLP File for SwingSet2 Demo Application -->
    <title>Webstart 6 Bugreport</title>
    <vendor>Skillworks AG</vendor>
    <description kind="short">None</description>
    <j2se version="1.5"/>
    <nativelib href="jws6-bugreport-native.jar"/>

<jar href="jws6-bugreport-app-1.0.jar" main="true"/>
<jar href="jws6-bugreport-jni-1.0.jar"/>

  <application-desc main-class="bugreport.jws6.ApplicationStarter"/>

Here the native code:

public class NativeInterface {

    public native String doSomething();

#include "NativeInterface.h"

  (JNIEnv *jEnv, jobject obj)

    jstring referenceKey = jEnv->NewStringUTF("Native Call done");
    return referenceKey;

/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class bugreport_jws6_NativeInterface */

#ifndef _Included_bugreport_jws6_NativeInterface
#define _Included_bugreport_jws6_NativeInterface
#ifdef __cplusplus
extern "C" {
 * Class: bugreport_jws6_NativeInterface
 * Method: doSomething
 * Signature: ()Ljava/lang/String;
  (JNIEnv *, jobject);

#ifdef __cplusplus

Does anybody help me with that problem...?
Thanks for every hint

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