Why do I get ClassNotPersistableException while ru

Question

I am randomly getting an org.datanucleus.exceptions.ClassNotPersistableException when I try to perform a query on the local JDO data store of my GWT/App Engine application. This only happens when I run the application on Hosted mode. When I deploy it to the Google App Engine everything works perfectly.

Stack Trace:

org.datanucleus.exceptions.ClassNotPersistableException: The class "com.wayd.server.beans.WinePost" is not persistable. This means that it either hasnt been enhanced, or that the enhanced version of the file is not in the CLASSPATH (or is hidden by an unenhanced version), or the Meta-Data/annotations for the class are not found.
    at org.datanucleus.jdo.NucleusJDOHelper.getJDOExceptionForNucleusException(NucleusJDOHelper.java:305)
    at org.datanucleus.ObjectManagerImpl.getExtent(ObjectManagerImpl.java:3700)
    at org.datanucleus.jdo.JDOPersistenceManager.getExtent(JDOPersistenceManager.java:1515)
    at com.wayd.server.WinePostServiceImpl.getPosts(WinePostServiceImpl.java:212)
    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:585)
    at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:527)
    ... 25 more
Caused by: org.datanucleus.exceptions.ClassNotPersistableException: The class "com.wayd.server.beans.WinePost" is not persistable. This means that it either hasnt been enhanced, or that the enhanced version of the file is not in the CLASSPATH (or is hidden by an unenhanced version), or the Meta-Data/annotations for the class are not found.
    at org.datanucleus.ObjectManagerImpl.assertClassPersistable(ObjectManagerImpl.java:3830)
    at org.datanucleus.ObjectManagerImpl.getExtent(ObjectManagerImpl.java:3693)
    ... 32 more)

WinePost class is a very simple JDO persistence capable class:

@PersistenceCapable(identityType = IdentityType.APPLICATION) public class WinePost {

@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
private Long id;

@Persistent
private User author;

@Persistent
private String grape;

@Persistent
private String comment;

public WinePost(final User author, final String grape,
        final String comment) {
    super();
    this.grape = grape;
    this.comment = comment;
}

public User getAuthor() {
    return author;
}

public void setAuthor(final User author) {
    this.author = author;
}

public Long getId() {
    return id;
}

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

public String getGrape() {
    return grape;
}

public void setGrape(final String grape) {
    this.grape = grape;
}

public String getComment() {
    return comment;
}

public void setComment(final String comment) {
    this.comment = comment;
}

public String getUserNickname() {
    String retVal = null;
    if (author != null) {
        retVal = author.getNickname();
    }
    return retVal;
}

public WinePostModel getWinePostModel() {
    final WinePostModel winePostModel = new WinePostModel(grape, vintage, getUserNickName());
    return winePostModel;
}

}

The datastore query is performed by the following method:

public ArrayList<WinePostModel> getPosts() {
        final ArrayList<WinePostModel> posts = new ArrayList<WinePostModel>();
        final PersistenceManager persistenceManager = PMF.get()
        .getPersistenceManager();

        final Extent<WinePost> winePostExtent = persistenceManager.getExtent(
                WinePost.class, false);
        for (final WinePost winePost : winePostExtent) {
            posts.add(winePost.getWinePostModel());
        }
        winePostExtent.closeAll();

        return posts;
    }

Answer 1

I had the same issue. In my case the code was correctly processed during building via maven clean + install, see below the excerpt from the logging:

ENHANCED (Persistable) : nl.jdoexample.model.Product ENHANCED (Persistable) : nl.jdoexample.model.Book

What went wrong was that when executing (in Intellij) prior to the execution (see for this Run / Debug Configurations) the command 'make' was executed, thereby removing the enhanced java files. This caused the error to pop up.

Reparation of the problem in Intellij (but can also be done in Eclipse or Netbeans): - jdo-example - Lifecycle: - edit configuration (Run / Debug Configurations): - jdo-example [install] Command line: clean install

• Run / Debug Configurations: -Application: - Remove 'make' - New execution definition: - Name: execute main jdoExample - Configuration: - Main class: nl.jdoexample.main

In this way the application will not be compiled again before execution, thereby removing the enhanced java files. This was successful in my situation. Hope this helps.