Java LIbrairies Dynamic loadings

[nde...@yahoo.de]

Hello,
i try to load dynamically some Librairies, but i have this Error Message:
java.lang.ClassNotFoundException: jboss-deployment.jar
    at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
    at 
org.nabucco.testautomation.jenkins.plugin.ClassLoading.setClasspath(ClassLoading.java:64)

here is how i do it :

            try {
                jarUrl = files[i].toURL();

                System.out.println(files[i].getName() + " was created." + 
jarUrl);
            } catch (MalformedURLException e1) {
                System.out.println("Jar-URl was not created.");
                e1.printStackTrace();
            }
            URL[] filesUrls = new URL[] { jarUrl };
            URLClassLoader ucl = new URLClassLoader(filesUrls);
            Class c = ucl.loadClass(files[i].getName());
can somebody help me?
thanks, 
Gil