Mongo java.lang.IllegalArgumentException: can't serialize class java.lang.Class

Question

I'm using Java+Spring+MongoTemplate+MongoDB. If I wanna to insert object into my MongoDB then I've got error:

 java.lang.IllegalArgumentException: can't serialize class java.lang.Class

Here is my mongo-context.xml:

    <mongo:mongo id="mongoLocal" host="${local.mongo.host}" port="${local.mongo.port}">
    <mongo:options
            connections-per-host="700"
            threads-allowed-to-block-for-connection-multiplier="100"
            connect-timeout="15000"
            auto-connect-retry="true"
            socket-timeout="60000"
            write-number="1"/>
</mongo:mongo>

<mongo:db-factory id="mongoDbFactoryLocal" dbname="${local.mongo.db}" mongo-ref="mongoLocal"/>

<bean id="mongoConverterLocal" class="org.springframework.data.mongodb.core.convert.MappingMongoConverter">
    <constructor-arg index="0" ref="mongoDbFactoryLocal" />
    <constructor-arg index="1">
        <bean class="org.springframework.data.mongodb.core.mapping.MongoMappingContext" />
    </constructor-arg>
    <property name="mapKeyDotReplacement" value="\+"/>
</bean>

<bean id="mongoTemplateLocal" class="org.springframework.data.mongodb.core.MongoTemplate">
    <constructor-arg name="mongoDbFactory" ref="mongoDbFactoryLocal"/>
    <constructor-arg name="mongoConverter" ref="mongoConverterLocal"/>
</bean>

mongo-context.xml I imported to spring-context.xml and use it like:

   <bean id="statusDao" class="com.status.StatusDAOImpl">
   </bean>

   <bean id="BasicDAO" class="com.status.PreparableDAO">
          <property name="daos">
                 <list>
                        <ref bean="statusDao"/>
                 </list>
          </property>
          <property name="template" ref="mongoTemplateLocal"/>              
   </bean>

And finally class (SimpleMessage) that I'm trying to insert into Mongo:

    public abstract class Message implements Serializable {

    @Id
    private String id;

    public Message() {super();}

    public Message(String id) {
        this.id = id;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }
}

and

      @Document
public class EmlMessage extends Message {

    private WatchEvent.Kind<Path> eventType;
    private String emlPath;

    public EmlMessage() {
        super();
    }

    public EmlMessage(String id,
                      WatchEvent.Kind<Path> eventType,
                      StatusType statusType,
                      String emlPath) {

        super(id, statusType);
        this.eventType = eventType;
        this.emlPath = emlPath;
    }

    public EmlMessage(String id,
                      String eventType,
                      StatusType statusType,
                      String emlPath) {

        super(id, statusType);
        this.emlPath = emlPath;
        chooseEventType(eventType);
    }

    public WatchEvent.Kind<Path> getEventType() {
        return eventType;
    }

    public void setEventType(WatchEvent.Kind<Path> eventType) {
        this.eventType = eventType;
    }

    public void setEventType(String eventType) {
        chooseEventType(eventType);
    }

    private void chooseEventType(String eventType) {

        if (eventType.equalsIgnoreCase("ENTRY_CREATE"))
            this.eventType = StandardWatchEventKinds.ENTRY_CREATE;
        else if (eventType.equalsIgnoreCase("ENTRY_MODIFY"))
            this.eventType = StandardWatchEventKinds.ENTRY_MODIFY;
        else if (eventType.equalsIgnoreCase("ENTRY_DELETE"))
            this.eventType = StandardWatchEventKinds.ENTRY_DELETE;
        else
            this.eventType = null;

    }

    @Override
    public int hashCode() {
        int hash = 1;
        hash = hash * 31 + (getId() == null ?
                "".hashCode() : getId().hashCode());       
        hash = hash
                + (arriveDateTime == null ? 0 : arriveDateTime.hashCode());

        return hash;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;

        if (!(obj instanceof EmlMessage))
            return false;

        SimpleMessage otherA = (SimpleMessage) obj;
        return getId().equals(otherA.getId());
    }
}

Any idea? I know that I can extends BasicDBObject, but why I need to do it if I implemented MongoMappingConverter.

Answer 1

Problem was in variable WatchEvent.Kind of java.nio.file.StandardWatchEventKinds. This class is public final class StandardWatchEventKinds. I just switched into String. Now it's looking like

 @Document
public class EmlMessage extends Message {

    private String eventType;
    private String emlPath;

    public EmlMessage() {
        super();
    }

    public EmlMessage(String id,
                      WatchEvent.Kind<Path> eventType,
                      StatusType statusType,
                      String emlPath) {

        super(id, statusType);
        this.eventType = eventType.name();
        this.emlPath = emlPath;
    }

    public EmlMessage(String id,
                      String eventType,
                      StatusType statusType,
                      String emlPath) {

        super(id, statusType);
        this.emlPath = emlPath;
        this.eventType = eventType;
    }

    public String getEventType() {
        return eventType;
    }

    public void setEventType(WatchEvent.Kind<Path> eventType) {
        this.eventType = eventType.name();
    }

    public void setEventType(String eventType) {
        this.eventType = eventType;
    }

    public String getEmlPath() {
        return emlPath;
    }

    public void setEmlPath(String emlPath) {
        this.emlPath = emlPath;
    }