EclipseLink MOXy with spring MVC for RESTful services not working for JSON

Question

Here is the situation.

When I use EclipseLink MOXy with Spring 3 MVC to generate JSON output it throws following exception when I try to set the json media type with following statement.

marshaller.setProperty(JAXBContextProperties.MEDIA_TYPE, "application/json");

javax.xml.bind.PropertyException: name: eclipselink.media-type value: application/json
    at org.eclipse.persistence.jaxb.JAXBMarshaller.setProperty(JAXBMarshaller.java:520)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:176)
    at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:436)
    at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:424)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:790)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:719)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:669)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:574)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
    at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227)
    at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125)

I am using JAXBviews too to generate xml output for other services in the application. Here is the beans declaration in application-context.xml for the same.

<bean id="jaxbMarshaller"    class="com.abc.restws.marshallers.ClasspathScanningJaxb2Marshaller">
    <property name="basePackages" ref="jaxbBasePackages" />
</bean> 


    <bean id="jaxbMarshallingView" class="org.springframework.web.servlet.view.xml.MarshallingView">
        <property name="marshaller" ref="jaxbMarshaller"/>
    </bean> 
    <bean id="jaxbJsonMarshallingView" class="org.springframework.web.servlet.view.xml.MarshallingView">
        <property name="contentType" value="application/json"/>
        <property name="marshaller" ref="jaxbJsonMarshaller"/>
    </bean> 

What's the reason for this error? How can i fix this error? XML output is generated fine but for JSON it throws this exception. You can see in the exception details it's using correct JAXBMarshaller class too to set the json media type. Please advice.

"org.eclipse.persistence.jaxb.JAXBMarshaller.setProperty(JAXBMarshaller.java:520)"

Answer 1

Note: I'm the EclipseLink JAXB (MOXy) lead and a member of the JAXB (JSR-222) expert group.

JSON binding was added to EclipseLink in version 2.4, and you are using WebLogic 10.3.4 (11g) which contains EclipseLink 2.1.2. The recommended solution to this problem is to create a shared library in WebLogic for the newer release of EclipseLink.

CREATE THE SHARED LIBRARY

WebLogic has the concept of shared libraries. These are deployed as an EAR. Below is what the EAR will look like for creating a shared library for EclipseLink 2.4.

EclipseLink24.ear

• lib/eclipselink.jar
• META-INF/application.xml
• META-INF/MANIFEST.MF
• META-INF/weblogic-application.xml

application.xml

<application>
  <display-name>EclipseLink 2.4 Shared Library</display-name>
  <module>
    <java></java>
  </module>
</application>

MANIFEST.MF

Manifest-Version: 1.0
Ant-Version: Apache Ant 1.8.2
Created-By: 1.7.0_04-b21 (Oracle Corporation)
Extension-Name: EclipseLink-2.4.0
Specification-Version: 2.4.0
Implementation-Version: 2.4.0.v20120608-r11652

weblogic-application.xml

<weblogic-application>
  <prefer-application-packages>
    <package-name>org.eclipse.persistence.*</package-name>
  </prefer-application-packages>
</weblogic-application>

USE THE SHARED LIBRARY

Once the shared library has been deployed, you need to configure your enterprise applications to use it.

SampleApplication.ear

• META-INF/MANIFEST.MF
• META-INF/weblogic-application.xml
• SampleApplication.war

weblogic-application.xml

The weblogic-application.xml file is used to reference the shared library. The entries in the library-ref element need to match the corresponding entries from MANIFEST.MF in the shared library.

<?xml version="1.0" encoding="UTF-8"?>
<wls:weblogic-application xmlns:wls="http://xmlns.oracle.com/weblogic/weblogic-application" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/javaee_5.xsd http://xmlns.oracle.com/weblogic/weblogic-application http://xmlns.oracle.com/weblogic/weblogic-application/1.2/weblogic-application.xsd">
    <!--weblogic-version:10.3.4-->
    <wls:application-param>
        <wls:param-name>webapp.encoding.default</wls:param-name>
        <wls:param-value>UTF-8</wls:param-value>
    </wls:application-param>
    <wls:library-ref>
        <wls:library-name>EclipseLink-2.4.0</wls:library-name>
        <wls:specification-version>2.4.0</wls:specification-version>
        <wls:implementation-version>2.4.0.v20120608-r11652</wls:implementation-version>
        <wls:exact-match>true</wls:exact-match>
    </wls:library-ref>
</wls:weblogic-application>

TestServlet

Below is a test servlet that you could include in the WAR to test the EclipseLink version.

package com.example;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class TestServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    public TestServlet() {
        super();
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        out.append("<html><body>");
        out.append(org.eclipse.persistence.Version.getVersion());
        out.append("</body></html>");
    }

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

}

For More Information

• http://buttso.blogspot.com/2011/07/plugging-in-later-version-of.html