我喜欢打电话给RMI，但是例外被限制了。它有什么问题？

线程"main"java. rmi.UnmarshalException中的异常：错误解组返回；嵌套异常是：java.lang.ClassNotFoundException：test.Hello（无安全管理器：禁用了RMI类加载器）at sun.rmi.在com.xx.rmiproxy.RmiProxy.main（RmiProxy.java:18）atcom.xx.rmiproxy.RmiProxy.call（RmiProxy.java:39）at java.lang.ClassNotFoundException：test.Hello（无安全管理器：禁用了RMI类加载器）at sun.rmi.server.LoaderHandler.loadProxyClass（未知源）at java.rmi.server.RMIClassLoader2 dolls.loadProxyClass（未知源）

public String call(String rmiId, String json) throws Exception{

    RmiInterfaceDescription desc = dao.getDescriptionById(rmiId);
    desc.setJarFile("d:\\test.jar");

    RmiClientClassLoader rmiClassLoader = new RmiClientClassLoader(null,desc);

    Class interfaceClass = rmiClassLoader.loadClass(desc.getInterfaceName());
    List<String> paraClasses = desc.getParaClasses();

    Class returnClass = rmiClassLoader.loadClass(desc.getReturnClass());

    Object obj = Naming.lookup(desc.getRmiUrl());

    Class[] parameterTypes = new Class[paraClasses.size()];

    for(int i=0;i<paraClasses.size();i++){
        parameterTypes[i]= rmiClassLoader.loadClass(paraClasses.get(i));
    }

    Method method = interfaceClass.getDeclaredMethod(desc.getMethodName(),
            parameterTypes);

    Object params[] = parseParamsFromJson();
    Object result = method.invoke(obj, "ssd");


    return encode(result);
}

.....

public class RmiClientClassLoader extends URLClassLoader {
public static void main(String args[]) throws Exception {
    RmiInterfaceDescription description = new RmiInterfaceDescription();

    description.setJarFile("d:\\test.jar");
    RmiClientClassLoader cl = new RmiClientClassLoader(null, description);

    Class clientClass = cl.loadClass("test.client.HelloClient");
}

private String basedir;
private RmiInterfaceDescription description;

@SuppressWarnings("deprecation")
public RmiClientClassLoader(String basedir,
        RmiInterfaceDescription description) throws MalformedURLException {
    super(new URL[] { new File(description.getJarFile()).toURL() });
    this.basedir = basedir;
    this.description = description;

}