Great tip, thanks, I will definitely try that. Just one note which I haven’t found an answer for in the docs for the outdated DataNucleus 1.x (current is 3.x!) — the list of classes to autoload persistence management for is just the class names or fully qualified names (I mean, with packages)?
On 5 srp, 15:13, Rolf Aden <[email protected]> wrote: > Looking at the comment in > org.datanucleus.store.appengine.DatastoreManager.getDatastoreClass() > could lead one to think, there are race conditions related to > initializing the meta-data of persistent classes. Since your problem > occurs only from time to time, it could point to the same direction. > > If you are using JDO, you may want to try to use the datanucleus > "Automatic Startup" mechanism (http://www.datanucleus.org/products/ > accessplatform/jdo/autostart.html) to get more control over the > process of initializing the class meta data. > > E.g. in jdoConfig.xml add these properties: > <property name="datanucleus.autoStartClassNames" > value="class1,class2,class3,…" /> > <property name="datanucleus.autoStartMechanism" value="Classes" /> > > Rolf > > On 4 Aug., 12:43, Pavel Lisa <[email protected]> wrote: > > > > > > > > > From time to time, org.datanucleus.store.appengine.DatastoreTable throws a > > NullPointerException, and I have not yet figured out why or what is the > > pattern, just a few first requests fail and then all goes well. > > > The exact line where the exception is thrown is 569: > > > // Run callbacks for each of the element classes. > > > for (AbstractClassMetaData elementCmd1 : elementCmds) { > > > callbacks.put(elementCmd1.getFullClassName(), > > > new CallBack(fmd, cmd.getFullClassName())); > > > DatastoreTable dt = > > > (DatastoreTable) storeMgr > > > .getDatastoreClass(elementCmd1.getFullClassName(), clr); > > > dt.runCallBacks(); // This line throws java.lang.NullPointerException from > > time to time > > > if (fmd.getMappedBy() != null) { > > > // This element type has a many-to-one pointing back. > > > // We assume that our pk is part of the pk of the element type. > > > dt.markFieldAsParentKeyProvider(fmd.getMappedBy()); > > > } > > } > > > Anyone has an idea why this happens? -- You received this message because you are subscribed to the Google Groups "Google App Engine for Java" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-appengine-java?hl=en.
