Error when marshaling wps LiteralValue

[ryeats]

Getting this error when marshaling WPS 2.0 LiteralValue objects:

Instance of "net.opengis.wps.v_2_0.LiteralValue" is substituting "net.opengis.ows.v_2_0.ValueType", but "net.opengis.wps.v_2_0.LiteralValue" is bound to an anonymous type.. Instance of "net.opengis.wps.v_2_0.LiteralValue" is substituting "net.opengis.ows.v_2_0.ValueType", but "net.opengis.wps.v_2_0.LiteralValue" is bound to an anonymous type..

Looking at the generated code for LiteralValue it has a @XmlType(name = "") which is causing the issue and seems to be coming from the nested complexType.

[ryeats]

Created a PR with a proposed fix #190