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Calling the <code>makePersistent()</code> method doesn't write to the datastore; closing the PersistenceManager or committing your changes does. Since you haven't done this when you run your query, you're getting all objects from the datastore which does not, yet, include the object you just called makePersistent on. Read about object states here: <a href="http://db.apache.org/jdo/state_transition.html" rel="nofollow">http://db.apache.org/jdo/state_transition.html</a> There are two ways around this, you can put this inside a transaction since the commit writes to the datastore (keep in mind GAE 5 transaction/entity type limit on transactions) and commit before running your query; Example using transaction... <pre><code>public Collection<MyObject> add(MyObject o) { PersistenceManager pm = PMF.get().getPersistenceManager(); ArrayList<MyObject> list = null; try { Transaction tx=pm.currentTransaction(); try { tx.begin(); pm.makePersistent(o); tx.commit(); } finally { if (tx.isActive()) { tx.rollback(); } } Query query = pm.newQuery(MyObject.class); List<MyObject> rs = (List<MyObject>) query.execute(); ArrayList<MyObject> list = new ArrayList<MyObject>(); for (MyObject r : rs) { list.add(r); } } finally { pm.close(); } return list; } </code></pre> or you could close the persistence manager after calling makePersistent on o and then open another one to run your query on. <pre><code>// Note that this only works assuming the makePersistent call is successful public Collection<MyObject> add(MyObject o) { PersistenceManager pm = PMF.get().getPersistenceManager(); try { pm.makePersistent(o); } finally { pm.close(); } pm = PMF.get().getPersistenceManager(); ArrayList<MyObject> list = null; try { Query query = pm.newQuery(MyObject.class); List<MyObject> rs = (List<MyObject>) query.execute(); list= new ArrayList<MyObject>(); for (MyObject r : rs) { list.add(r); } } finally { pm.close(); } return list; } </code></pre> NOTE: I originally said you could just add <code>o</code> to the result list before returning; but that isn't a smart thing to do since in the event that there is a problem writing <code>o</code> to the datastore; then the returned list wouldn't reflect the actual data in the datastore. Doing what I now have (committing a transaction or closing the pm and then getting another one) should work since you have your datastoreReadPolicy set to STRONG.
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1. COI tried both approaches and wrapping read and write in two different transactions. Sometimes it works and sometimes it doesn't, this is seriously messed up. I cleaned the project, downgraded to jdk6 now I'm out of options. I even call flush and constancyCheck after committing, but it all doesn't help. Sometimes the data just doesn't get into the datastore fast enough. Your earlier idea with adding the new object to the results manually. I did that, but then I sometimes get problems one request later, because that value still isn't in the store. A browser refresh does the trick then (mostly?).
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2. COAre you doing any kind of caching; either with some kind of Map or through the Memcache api?
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