jaxrs/src/main/java/org/jboss/as/jaxrs/deployment/JaxrsMethodParameterProcessor.java
private Class checkParamType(Type genParamType, final Method method,
                                 final int paramPos, final ClassLoader classLoader){

        Class paramClazz = null;

        if (genParamType instanceof ParameterizedType) {
            ParameterizedType pType = (ParameterizedType) genParamType;
            Type[] actualTypeArgs = pType.getActualTypeArguments();
            // skip Map types. Don't know how to set default value for these
            if (actualTypeArgs.length == 1) {
                try {
                    paramClazz = classLoader.loadClass(actualTypeArgs[0].getTypeName());
                } catch (Exception ee) {
                    JAXRS_LOGGER.classIntrospectionFailure(ee.getClass().getName(),
                            ee.getMessage());
                }
            }
        } else {
            Class<?>[] paramArr = method.getParameterTypes();
            if (paramArr[paramPos].isArray()) {
                Class compClazz = paramArr[paramPos].getComponentType();
                if (!compClazz.isPrimitive()) {
                    paramClazz = compClazz;
                }
            } else {
                if (!paramArr[paramPos].isPrimitive()) {
                    paramClazz = paramArr[paramPos];
                }
            }
        }
        return paramClazz;
    }
private Class checkParamType(Type genParamType, final Method method,
                                 final int paramPos, final ClassLoader classLoader){

        Class paramClazz = null;

        if (genParamType instanceof ParameterizedType) {
            ParameterizedType pType = (ParameterizedType) genParamType;
            Type[] actualTypeArgs = pType.getActualTypeArguments();
            // skip Map types. Don't know how to set default value for these
            if (actualTypeArgs.length == 1) {
                try {
                    paramClazz = classLoader.loadClass(actualTypeArgs[0].getTypeName());
                } catch (Exception ee) {
                    JAXRS_LOGGER.classIntrospectionFailure(ee.getClass().getName(),
                            ee.getMessage());
                }
            }
        } else {
            Class<?>[] paramArr = method.getParameterTypes();
            if (paramArr[paramPos].isArray()) {
                Class compClazz = paramArr[paramPos].getComponentType();
                if (!compClazz.isPrimitive()) {
                    paramClazz = compClazz;
                }
            } else {
                if (!paramArr[paramPos].isPrimitive()) {
                    paramClazz = paramArr[paramPos];
                }
            }
        }
        return paramClazz;
    }
Take steps to properly identify the parameter's data type
@param genParamType
@param method
@param paramPos
@param classLoader
@return