Jackson is throwing a weird exception that I don't know how to fix. I'm using Spring, Hibernate and Jackson.
I have already considered that lazy-loading is causing the problem, but I have taken measures to tell Jackson to NOT process various properties as follows:
@JsonIgnoreProperties({ "sentMessages", "receivedMessages", "educationFacility" })
public class Director extends UserAccount implements EducationFacilityUser {
....
}
I have done the same thing for all the other UserAccount subclasses as well.
Here's the exception being thrown:
org.codehaus.jackson.map.JsonMappingException: No serializer found for class org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationConfig.Feature.FAIL_ON_EMPTY_BEANS) ) (through reference chain: java.util.ArrayList[46]->jobprep.domain.educationfacility.Director_$$_javassist_2["handler"])
at org.codehaus.jackson.map.ser.StdSerializerProvider$1.serialize(StdSerializerProvider.java:62)
at org.codehaus.jackson.map.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:268)
at org.codehaus.jackson.map.ser.BeanSerializer.serializeFields(BeanSerializer.java:146)
at org.codehaus.jackson.map.ser.BeanSerializer.serialize(BeanSerializer.java:118)
at org.codehaus.jackson.map.ser.ContainerSerializers$IndexedListSerializer.serializeContents(ContainerSerializers.java:236)
at org.codehaus.jackson.map.ser.ContainerSerializers$IndexedListSerializer.serializeContents(ContainerSerializers.java:189)
at org.codehaus.jackson.map.ser.ContainerSerializers$AsArraySerializer.serialize(ContainerSerializers.java:111)
at org.codehaus.jackson.map.ser.StdSerializerProvider._serializeValue(StdSerializerProvider.java:296)
at org.codehaus.jackson.map.ser.StdSerializerProvider.serializeValue(StdSerializerProvider.java:224)
at org.codehaus.jackson.map.ObjectMapper.writeValue(ObjectMapper.java:925)
at org.springframework.http.converter.json.MappingJacksonHttpMessageConverter.writeInternal(MappingJacksonHttpMessageConverter.java:153)
Suggestions on how I can get more info to see what's causing this? Anyone know how to fix it?
EDIT: I discovered that getHander() and other get*() methods exist on the proxy object. GRR!! Is there any way I can tell Jackson to not process anything on the proxy, or am I sol? This is really weird because the method that spits out the JSON only crashes under certain circumstances, not all the time. Nonetheless, it's due to the get*() methods on the proxy object.
Aside: Proxies are evil. They disrupt Jackson, equals() and many other parts of regular Java programming. I am tempted to ditch Hibernate altogether :/
I had a similar problem with lazy loading via the hibernate proxy object. Got around it by annotating the class having lazyloaded private properties with:
@JsonIgnoreProperties({"hibernateLazyInitializer", "handler"})
I assume you can add the properties on your proxy object that breaks the JSON serialization to that annotation.