VirtualAttributeCfgDefn definition =
VirtualAttributeCfgDefn.getInstance();
ClassPropertyDefinition propertyDefinition =
definition.getJavaClassPropertyDefinition();
Class<? extends VirtualAttributeProvider> providerClass =
propertyDefinition.loadClass(className,
VirtualAttributeProvider.class);
VirtualAttributeProvider<? extends VirtualAttributeCfg> provider =
(VirtualAttributeProvider<? extends VirtualAttributeCfg>)
providerClass.newInstance();