1 Reply Latest reply on Apr 27, 2011 10:15 AM by thomasseirer

JAXB issue: cannot marshall Java object graph to XML in Servlet - nor any of its super class is known to this context

thomasseirer Apr 27, 2011 10:11 AM

(Java version 1.6.0_24 and JBoss AS 6.0.0.Final (applies also to JBoss 5.1))

Trying to marshall an Java object graph to XML in a servlet I get the following apparently well known exception:

22:20:10,140 ERROR [STDERR] javax.xml.bind.MarshalException

22:20:10,140 ERROR [STDERR] - with linked exception:

22:20:10,140 ERROR [STDERR] [javax.xml.bind.JAXBException: class YY.XXX.printservice.domain.EmployeeDetails nor any of its super class is known to this context.]

(Note: I renamed the package name.)

When I try google for this problem I get hits galore.

But with the solutions and hints offered - for example the use of @XmlSeeAlso - I still wasn't able to solve the problem...

The strange thing about this is also that it works when the marshalling is done by a standalone client.

These are the two value classes involved:

1. class Report:

{code}

@XmlRootElement(name="report")

@XmlAccessorType(XmlAccessType.FIELD)

@XmlSeeAlso(EmployeeDetails.class)

public class Report implements Serializable {

@XmlElement(name="employee", type=YY.XXXX.printservice.domain.EmployeeDetails.class)

private List<EmployeeDetails> employeeDetails;

public Report(){

}

public Report(List<EmployeeDetails> employeeDetails) {

this.employeeDetails = employeeDetails;

}

public List<EmployeeDetails> getEmployeeDetails() {

return employeeDetails;

}

public void setEmployeeDetails(List<EmployeeDetails> employeeDetails) {

this.employeeDetails = employeeDetails;

}

{code}

2. class EmployeeDetails:

{code}

@XmlType(

propOrder = {

"employeeId"

, "firstName"

, "lastName"

, "departmentName"

, "jobTitle"

, "salary"

}

)

@XmlAccessorType(XmlAccessType.FIELD)

public class EmployeeDetails implements Serializable {

private Long employeeId;

private String firstName;

private String lastName;

private String departmentName;

private String jobTitle;

private Float salary;

public EmployeeDetails(){

}

public EmployeeDetails(Long employeeId

, String firstName

, String lastName

, String departmentName

, String jobTitle

, Float salary) {

this.employeeId = employeeId;

this.firstName = firstName;

this.lastName = lastName;

this.departmentName = departmentName;

this.jobTitle = jobTitle;

this.salary = salary;

}

public Long getEmployeeId() {

return employeeId;

}

public void setEmployeeId(Long employeeId) {

this.employeeId = employeeId;

}

public String getFirstName() {

return firstName;

}

public void setFirstName(String firstName) {

this.firstName = firstName;

}

public String getLastName() {

return lastName;

}

public void setLastName(String lastName) {

this.lastName = lastName;

}

public String getDepartmentName() {

return departmentName;

}

public void setDepartmentName(String departmentName) {

this.departmentName = departmentName;

}

public String getJobTitle() {

return jobTitle;

}

public void setJobTitle(String jobTitle) {

this.jobTitle = jobTitle;

}

public Float getSalary() {

return salary;

}

public void setSalary(Float salary) {

this.salary = salary;

}

{code}

The relevant parts of the servlet:

{code}

public final class PrintServlet extends HttpServlet {

private static final long serialVersionUID = 1L;

@EJB(mappedName="EmployeeBean/local")

private EmployeeLocal employeeBean;

private static JAXBContext jaxbContext = null;

private FopFactory fopFactory = FopFactory.newInstance();

private TransformerFactory transformerFactory = TransformerFactory.newInstance();

private DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();

public PrintServlet() {

super();

}

public void init() throws ServletException {

try {

jaxbContext = JAXBContext.newInstance( new Class[] {Report.class});

}

catch (JAXBException exception) {

exception.printStackTrace();

throw new ServletException( exception.fillInStackTrace() );

}

protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

String content = "application/x-java-serialized-object";

response.setContentType(content);

try {

List<EmployeeDetails> employeeDetailsList = employeeBean.getDetailsForAllEmployees();

Report report = new Report();

report.setEmployeeDetails(employeeDetailsList);

DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();

Document document = documentBuilder.newDocument();

jaxbContext.createMarshaller().marshal(report, document);

....

{code}

Calling toString on the JAXBContext instance in the servlet shows this:

22:20:09,656 INFO [STDOUT] vfs:/D:/server/jboss-6.0.0.Final/lib/jaxb-impl.jar/com/sun/xml/bind/v2/runtime/JAXBContextImpl.class Build-Id: 2.2

22:20:09,656 INFO [STDOUT] Classes known to this context:

22:20:09,656 INFO [STDOUT] [B

22:20:09,656 INFO [STDOUT] boolean

22:20:09,656 INFO [STDOUT] byte

22:20:09,656 INFO [STDOUT] char

22:20:09,656 INFO [STDOUT] com.sun.xml.bind.api.CompositeStructure

22:20:09,656 INFO [STDOUT] YY.XXX.printservice.domain.EmployeeDetails

22:20:09,656 INFO [STDOUT] YY.XXX.printservice.domain.Report

22:20:09,656 INFO [STDOUT] double

22:20:09,656 INFO [STDOUT] float

22:20:09,656 INFO [STDOUT] int

22:20:09,656 INFO [STDOUT] java.awt.Image

22:20:09,656 INFO [STDOUT] java.io.File

22:20:09,656 INFO [STDOUT] java.lang.Boolean

22:20:09,656 INFO [STDOUT] java.lang.Byte

22:20:09,656 INFO [STDOUT] java.lang.Character

22:20:09,656 INFO [STDOUT] java.lang.Class

22:20:09,656 INFO [STDOUT] java.lang.Double

22:20:09,656 INFO [STDOUT] java.lang.Float

22:20:09,656 INFO [STDOUT] java.lang.Integer

22:20:09,656 INFO [STDOUT] java.lang.Long

22:20:09,656 INFO [STDOUT] java.lang.Object

22:20:09,656 INFO [STDOUT] java.lang.Short

22:20:09,656 INFO [STDOUT] java.lang.String

22:20:09,656 INFO [STDOUT] java.lang.Void

22:20:09,656 INFO [STDOUT] java.math.BigDecimal

22:20:09,656 INFO [STDOUT] java.math.BigInteger

22:20:09,656 INFO [STDOUT] java.net.URI

22:20:09,656 INFO [STDOUT] java.net.URL

22:20:09,656 INFO [STDOUT] java.util.Calendar

22:20:09,656 INFO [STDOUT] java.util.Date

22:20:09,656 INFO [STDOUT] java.util.GregorianCalendar

22:20:09,656 INFO [STDOUT] java.util.UUID

22:20:09,656 INFO [STDOUT] javax.activation.DataHandler

22:20:09,656 INFO [STDOUT] javax.xml.bind.JAXBElement

22:20:09,656 INFO [STDOUT] javax.xml.datatype.Duration

22:20:09,656 INFO [STDOUT] javax.xml.datatype.XMLGregorianCalendar

22:20:09,656 INFO [STDOUT] javax.xml.namespace.QName

22:20:09,656 INFO [STDOUT] javax.xml.transform.Source

22:20:09,656 INFO [STDOUT] long

22:20:09,656 INFO [STDOUT] short

22:20:09,656 INFO [STDOUT] void

Calling toString on the JAXBContext instance of the standalone client shows this:

[java] jar:file:/D:/server/jboss-6.0.0.Final/client/jaxb-impl.jar!/com/sun/xml/bind/v2/runtime/JAXBContextImpl.class Build-Id: 2.2

[java] Classes known to this context:

[java] [B

[java] boolean

[java] byte

[java] char

[java] com.sun.xml.bind.api.CompositeStructure

[java] YY.XXX.printservice.domain.EmployeeDetails

[java] YY.XXX.printservice.domain.Report

[java] double

[java] float

[java] int

[java] java.awt.Image

[java] java.io.File

[java] java.lang.Boolean

[java] java.lang.Byte

[java] java.lang.Character

[java] java.lang.Class

[java] java.lang.Double

[java] java.lang.Float

[java] java.lang.Integer

[java] java.lang.Long

[java] java.lang.Object

[java] java.lang.Short

[java] java.lang.String

[java] java.lang.Void

[java] java.math.BigDecimal

[java] java.math.BigInteger

[java] java.net.URI

[java] java.net.URL

[java] java.util.Calendar

[java] java.util.Date

[java] java.util.GregorianCalendar

[java] java.util.UUID

[java] javax.activation.DataHandler

[java] javax.xml.bind.JAXBElement

[java] javax.xml.datatype.Duration

[java] javax.xml.datatype.XMLGregorianCalendar

[java] javax.xml.namespace.QName

[java] javax.xml.transform.Source

[java] long

[java] short

[java] void

Thus the two JAXBContext instances do not only know the same data types, but they also know the two relevant custom classes Report and EmployeeDetails.

But the similarity continues: Outputting the schema known to both JAXBContext instances shows that they are also the same.

1. server side:

22:20:09,859 INFO [STDOUT] <?xml version="1.0" encoding="UTF-8" standalone="yes"?>

22:20:09,859 INFO [STDOUT] <xs:schema version="1.0" xmlns:xs="http://www.w3.org/2001/XMLSchema">

22:20:09,859 INFO [STDOUT]

22:20:09,906 INFO [STDOUT] <xs:element name="report" type="report"/>

22:20:09,906 INFO [STDOUT]

22:20:09,906 INFO [STDOUT] <xs:complexType name="employeeDetails">

22:20:09,906 INFO [STDOUT] <xs:sequence>

22:20:09,906 INFO [STDOUT] <xs:element name="employeeId" type="xs:long" minOccurs="0"/>

22:20:09,906 INFO [STDOUT] <xs:element name="firstName" type="xs:string" minOccurs="0"/>

22:20:09,906 INFO [STDOUT] <xs:element name="lastName" type="xs:string" minOccurs="0"/>

22:20:09,906 INFO [STDOUT] <xs:element name="departmentName" type="xs:string" minOccurs="0"/>

22:20:09,906 INFO [STDOUT] <xs:element name="jobTitle" type="xs:string" minOccurs="0"/>

22:20:09,906 INFO [STDOUT] <xs:element name="salary" type="xs:float" minOccurs="0"/>

22:20:09,906 INFO [STDOUT] </xs:sequence>

22:20:09,906 INFO [STDOUT] </xs:complexType>

22:20:09,906 INFO [STDOUT]

22:20:09,906 INFO [STDOUT] <xs:complexType name="report">

22:20:09,921 INFO [STDOUT] <xs:sequence>

22:20:09,921 INFO [STDOUT] <xs:element name="employee" type="employeeDetails" minOccurs="0" maxOccurs="unbounded"/>

22:20:09,921 INFO [STDOUT] </xs:sequence>

22:20:09,921 INFO [STDOUT] </xs:complexType>

22:20:09,921 INFO [STDOUT] </xs:schema>

2. standalone client.

{code:xml}

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>

<xs:schema version="1.0" xmlns:xs="http://www.w3.org/2001/XMLSchema">

<xs:element name="report" type="report"/>

<xs:complexType name="report">

<xs:sequence>

<xs:element name="employee" type="employeeDetails" minOccurs="0" maxOccurs="unbounded"/>

</xs:sequence>

</xs:complexType>

<xs:complexType name="employeeDetails">

<xs:sequence>

<xs:element name="employeeId" type="xs:long" minOccurs="0"/>

<xs:element name="firstName" type="xs:string" minOccurs="0"/>

<xs:element name="lastName" type="xs:string" minOccurs="0"/>

<xs:element name="departmentName" type="xs:string" minOccurs="0"/>

<xs:element name="jobTitle" type="xs:string" minOccurs="0"/>

<xs:element name="salary" type="xs:float" minOccurs="0"/>

</xs:sequence>

</xs:complexType>

</xs:schema>

{code:xml}

Why is it that the marshalling in the servlet throws an Exception and the marshalling in the standalone client gives a result like this:

{code:xml}

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>

<firstName>Shelley</firstName>

<lastName>Higgins</lastName>

<departmentName>Accounting</departmentName>

<jobTitle>Accounting Manager</jobTitle>

</employee>

<firstName>William</firstName>

<lastName>Gietz</lastName>

<departmentName>Accounting</departmentName>

<jobTitle>Public Accountant</jobTitle>

</employee>

<firstName>Jennifer</firstName>

<lastName>Whalen</lastName>

<departmentName>Administration</departmentName>

<jobTitle>Administration Assistant</jobTitle>

</employee>

.....

</report>

{code:xml}

Thanks in advance.

1. JAXB issue: cannot marshall Java object graph to XML in Servlet - nor any of its super class is known to this context

thomasseirer Apr 27, 2011 10:15 AM (in response to thomasseirer)

Finally I found the right pointer:
http://forums.oracle.com/forums/thread.jspa?messageID=6859232&#6859232

The JAXBException was kind of misleading, because the whole thing was a classpath issue.
The way to do it was to pack the ejb jar, the webapplication and a lib with the JAXB annotated classes into an ear file and deploy this ear file to the server.

Apparently you can also place the JAXB annotated classes as an common lib in the lib directory of a war file.
In my case this wasn't possible, because the ejb package also had an dependency on the JAXB annotated classes.
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