clazz=Util.loadClass(protocol_name, this.getClass());
try { clazz=Util.loadClass(protocol_name, this.getClass()); } catch(ClassNotFoundException e) { }
        Protocol createLayer(ProtocolStack prot_stack) throws Exception {            Protocol retval=null;            if(protocol_name == null)                return null;            String defaultProtocolName=protocol_prefix + '.' + protocol_name;            Class clazz=null;            clazz=Util.loadClass(defaultProtocolName, this.getClass());            if(clazz == null) {                clazz=Util.loadClass(protocol_name, this.getClass());                if(clazz == null) {                    throw new Exception("unable to load class for protocol " + protocol_name +                            " (either as an absolute - " + protocol_name + " - or relative - " +                            defaultProtocolName + " - package name)!");                }            }            try {                retval=(Protocol)clazz.newInstance();                if(retval == null)                    throw new Exception("creation of instance for protocol " + protocol_name + "failed !");                retval.setProtocolStack(prot_stack);                if(properties != null)                    if(!retval.setPropertiesInternal(properties))                        return null;                retval.init();            }            catch(InstantiationException inst_ex) {                log.error("an instance of " + protocol_name + " could not be created. Please check that it implements" +                        " interface Protocol and that is has a public empty constructor !");                throw inst_ex;            }            return retval;        }