See: DocumentStyleMarshallerTestCase/DocumentStyleUnmarshallerTestCase

Expected:<ns1:echoString xmlns:ns1="http://org.jboss.ws/jaxrpc/types" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><String_1>Hello</String_1><String_2>world!</String_2></ns1:echoString>
Actual :<ns1:echoString xmlns:ns1="http://org.jboss.ws/jaxrpc/types" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><String_1 xsi:nil="1"></String_1><String_2 xsi:nil="1"></String_2></ns1:echoString>
at org.jboss.test.ws.JBossWSTest.assertEquals(JBossWSTest.java:86)
at org.jboss.test.ws.jaxb.DocumentStyleMarshallerTestCase.testEchoStringRequest(DocumentStyleMarshallerTestCase.java:82)

This issue is two fold:

First, the error reporting is poor. Internally the underscore is swallowed, which leads to not finding the appropriate accessor method.

Second, the accessor should be determined from the mapping meta data

This issue is critical, because wscompile generates underscores by default with bean properties.