title: jackson JodaTime DateTime is not serialized
body: <p>I am trying to start working with jackson for serializing objects having Joda <code>DateTime</code> members.</p>
  
  <p>I created the following serializer:</p>
  
  <pre><code>public class DateTimeSerializer extends JsonSerializer&lt;DateTime&gt; {
      private static DateTimeFormatter formatter = 
      DateTimeFormat.forPattern("dd-MM-yyyy HH:mm:ss, SSS [z]");
  
      @Override
      public void serialize(DateTime value, JsonGenerator gen, 
          SerializerProvider arg2) throws IOException,
          JsonProcessingException {
          gen.writeString(formatter.print(value));
      }
      @Override
      public Class&lt;DateTime&gt; handledType() { 
          return DateTime.class; 
      }
  }
  </code></pre>
  
  <p>and I am trying to serialize my class having <code>DateTime</code> members as follows:</p>
  
  <pre><code>    Version version = new Version(1, 0, 0, "SNAPSHOT");
      SimpleModule module = new SimpleModule("ZORRO", version);
      module = module.addSerializer(new DateTimeSerializer());
      // and so on...
      ObjectMapper mapper = new ObjectMapper();
      mapper.registerModule(module);
  
      mapper.writeValue(new File("C:\\tmp\\window1.json"), window1);
  </code></pre>
  
  <p>I am getting the following exception (I fail to understand what I was doing wrong):</p>
  
  <pre><code>java.lang.TypeNotPresentException: Type org.joda.convert.ToString not present
  at com.ibm.oti.reflect.AnnotationHelper.getAnnotation(AnnotationHelper.java:38)
  at com.ibm.oti.reflect.AnnotationHelper.getDeclaredAnnotations(AnnotationHelper.java:50)
  at com.ibm.oti.reflect.Method.getDeclaredAnnotations(Method.java:31)
  at java.lang.reflect.Method.getDeclaredAnnotations(Method.java:687)
  at org.codehaus.jackson.map.introspect.AnnotatedClass._addMixUnders(AnnotatedClass.java:973)
  at org.codehaus.jackson.map.introspect.AnnotatedClass._addMemberMethods(AnnotatedClass.java:637)
  at org.codehaus.jackson.map.introspect.AnnotatedClass.resolveMemberMethods(AnnotatedClass.java:413)
  at org.codehaus.jackson.map.introspect.BasicClassIntrospector.classWithCreators(BasicClassIntrospector.java:185)
  at org.codehaus.jackson.map.introspect.BasicClassIntrospector.collectProperties(BasicClassIntrospector.java:157)
  at org.codehaus.jackson.map.introspect.BasicClassIntrospector.forSerialization(BasicClassIntrospector.java:96)
  at org.codehaus.jackson.map.introspect.BasicClassIntrospector.forSerialization(BasicClassIntrospector.java:16)
  at org.codehaus.jackson.map.SerializationConfig.introspect(SerializationConfig.java:973)
  at org.codehaus.jackson.map.ser.BeanSerializerFactory.createSerializer(BeanSerializerFactory.java:251)
  at org.codehaus.jackson.map.ser.StdSerializerProvider._createUntypedSerializer(StdSerializerProvider.java:782)
  at org.codehaus.jackson.map.ser.StdSerializerProvider._createAndCacheUntypedSerializer(StdSerializerProvider.java:758)
  at org.codehaus.jackson.map.ser.StdSerializerProvider.findValueSerializer(StdSerializerProvider.java:380)
  at org.codehaus.jackson.map.ser.std.BeanSerializerBase.resolve(BeanSerializerBase.java:307)
  at org.codehaus.jackson.map.ser.impl.SerializerCache.addAndResolveNonTypedSerializer(SerializerCache.java:159)
  at org.codehaus.jackson.map.ser.StdSerializerProvider._createAndCacheUntypedSerializer(StdSerializerProvider.java:744)
  at org.codehaus.jackson.map.ser.StdSerializerProvider.findValueSerializer(StdSerializerProvider.java:344)
  at org.codehaus.jackson.map.ser.StdSerializerProvider.findTypedValueSerializer(StdSerializerProvider.java:420)
  at org.codehaus.jackson.map.ser.StdSerializerProvider._serializeValue(StdSerializerProvider.java:601)
  at org.codehaus.jackson.map.ser.StdSerializerProvider.serializeValue(StdSerializerProvider.java:256)
  at org.codehaus.jackson.map.ObjectMapper._configAndWriteValue(ObjectMapper.java:2575)
  at org.codehaus.jackson.map.ObjectMapper.writeValue(ObjectMapper.java:2048)
  </code></pre>