please include function toURL.

static Class hotwireCore(L<File> files) ctex {
  // make class loader
  JavaXClassLoader classLoader = hotwire_makeClassLoader(files);

  // load & return main class
  Class<?> theClass = classLoader.loadClass("main");
  
  setOpt(theClass, "__javax", getJavaX());
  setOpt(theClass, "programID", "#3999999");
  
  if (!_inCore())
    hotwire_copyOver(theClass);
  
  ret theClass;
}