Hey Alexey: I'm looking at the absolute latest JBoss XB (now, at least), specifically MarshallerImpl vs XercesXSMarshaller. It is plain to see (IMO) that MarshallerImpl does *not* throw any exceptions if a required attribute is missing. I just ran a test to verify. I did manage to get one marshaller to throw such an exception (after slight modification). I took the XercesXSMarshaller's and added the following code starting at 695: | } // end if attrValue != null | else if( currentAttribute.getRequired()){ | // its required and is not present. Must throw exception | String name = currentAttribute.getAttrDeclaration().getName(); | throw new JBossXBRuntimeException("Required Attribute " + name + " is not present"); | } | Once I made this modification to XercesXSMarshaller, my test passed successfully. After reading your suggestion about MarshallerImpl, I switched to that marshaller, and the exact same test failed to throw any sort of JBossXBRuntimeExcepton of any sort for missing a required attribute. The test, plainly, is that my schema REQUIRES an attribute (such as "name") and I am trying to marshall an object lacking this attribute. Since I've found a workaround in my edits to XercesXSMarshaller, I can move forward with my project; but I think some similar functionality needs to be added to MarshallerImpl if you intend for it to replace XercesXSMarshaller. Hope all's well! Thanks for your help! - Rob Stryker View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4133725#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...