title: Issue with generate JAXB classes with value constructors
body: <p>I have to generate classes from XML Schema file using JAXB in Ant script. When I did it in default way, everything went good. Later I realized that I need value constructor for each class. I tried to use value-constructor plugin for XJC but when I ran Ant script I got an <a href="http://pastebin.com/zCmV6en5" rel="nofollow">error</a>:</p>
  
  <pre><code>BUILD FAILED
  c:\HOME\plt\owf2-testing\EdytorScenariuszy\build.xml:17:
  
      java.util.ServiceConfigurationError: com.sun.tools.xjc.Plugin: Provider org.jvnet.jaxb2_commons.plugin.value_constructor.ValueConstructorPlugin not a subtype
          at java.util.ServiceLoader.fail(ServiceLoader.java:214)
          at java.util.ServiceLoader.access$300(ServiceLoader.java:164)
          at java.util.ServiceLoader$LazyIterator.next(ServiceLoader.java:352)
          at java.util.ServiceLoader$1.next(ServiceLoader.java:428)
          at com.sun.tools.xjc.Options.findServices(Options.java:957)
          at com.sun.tools.xjc.Options.getAllPlugins(Options.java:374)
          at com.sun.tools.xjc.Options.parseArgument(Options.java:688)
          at com.sun.tools.xjc.Options.parseArguments(Options.java:809)
          at com.sun.tools.xjc.XJC2Task._doXJC(XJC2Task.java:474)
          at com.sun.tools.xjc.XJC2Task.doXJC(XJC2Task.java:457)
          at com.sun.tools.xjc.XJC2Task.execute(XJC2Task.java:380)
          at com.sun.istack.tools.ProtectedTask.execute(ProtectedTask.java:103)
          at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:292)
  </code></pre>
  
  <p>Here is my Ant <a href="http://pastebin.com/gq39zJ2c" rel="nofollow">script</a>:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8" standalone="yes"?&gt;
  &lt;project name="EdytorScenariuszy" default="createClasses"&gt;
  
          &lt;taskdef name="xjc" classname="com.sun.tools.xjc.XJCTask"&gt;
                  &lt;classpath&gt;
                          &lt;pathelement path="lib/jaxb-xjc.jar"/&gt;
                          &lt;pathelement path="lib/jaxb-impl.jar"/&gt;
                          &lt;pathelement path="lib/jaxb2-value-constructor.jar"/&gt;
                  &lt;/classpath&gt;
          &lt;/taskdef&gt;
  
          &lt;target name="clean"&gt;
                  &lt;delete dir="src/xml" /&gt;
          &lt;/target&gt;
  
          &lt;target name="createClasses" depends="clean"&gt;
                  &lt;xjc schema="scenariuszTestowy.xsd" binding="mapowanieTypow.xjb" destdir="src" package="xml"  encoding="UTF-8"&gt;
                          &lt;arg value="-Xvalue-constructor"/&gt;
                  &lt;/xjc&gt;
          &lt;/target&gt;
  &lt;/project&gt;
  </code></pre>
  
  <p>If anyone could help me how to deal with this exception I would be very grateful. </p>