Wrappers and non-existent classes and performance

[Benson Margulies]

JAX-WS like to look for non-existent classes. This costs something, by the
time that ClassLoaderUtils.loadClass gets done making three (or is it four?)
calls to the class loader. Are wrapper classes really legitimately possibly
defined in all those different class loaders? Should I make a negative cache
that recalls the nonexistence of classes once not found?