Custom RESTEasy StringConverter provider classes need special registration -------------------------------------------------------------------------- Key: JBSEAM-4020 URL: https://issues.jboss.org/browse/JBSEAM-4020 Project: Seam 2 Issue Type: Task Components: WS Reporter: Christian Bauer Fix For: 2.2.0.GA RESTEasy offers a custom StringConverter provider extension. Unlike normal providers, the SPI in RESTEasy for registration of these providers is different: if (StringConverter.class.isAssignableFrom(providerClass)) { providerFactory.addStringConverter(providerClass); } else { providerFactory.registerProvider(providerClass); } This needs to be fixed in RestEasyDispatcher.java