How do I debug?

[Samuel B. Quiring]

Greetings,   I have successfully compiled a schema.  I have an Eclipse project/program that is utilizing the generated classes.  The program reads in a SOAP file, breaks it apart, hands a SOAPElement to the parse() member, which returns a Document.  The code retrieves a simple value and prints it.  The value is correct!   However, the next value it retrieves is not so simple.  And that does not work, I get a null pointer exception.  How do I debug this?   The schema in question is http://era.nih.gov/Projectmgmt/SBIR/dev/personinforesponse.xsd.  Here's the excerpt that includes what's working and what's not:   <xs:element name="PersonAffiliationInfo">     <xs:complexType>         <xs:sequence>             <xs:group ref="rar:ContactPersonType" />             <xs:element name="PreferredAddressCode" type="pireq:YesNoIndicator" />             <xs:element name="Degree" type="xs:token" maxOccurs="unbounded" />             <xs:element name="PositionTitle" type="xs:token" />             <xs:element name="PriorGrant" type="nih:GrantNumberType" minOccurs="0" maxOccurs="unbounded" />         </xs:sequence>     </xs:complexType> </xs:element>   I am able to successfully retrieve the PositionTitle.  I am not able to retrieve the ContactPersonType, which comes from the schemas:     http://era.nih.gov/Projectmgmt/SBIR/dev/rarschema.xsd  and     http://era.nih.gov/Projectmgmt/SBIR/dev/commontypes.xsd   I have my fingers crossed that this works, but I'm starting to get nervous.   -Sam