db4o Developer Community

I have a reasonably fresh DB that is throwing a NPE when I try to open it with ObjectManager: We're using db4o-6.4.54.11278-java5.jar.  I tried to attached the offending DB, but the upload script is not responding saying the machine must be down.  I'll try again later. Any ideas why this is happening? Charlie Exception stack trace ...

Are the db4o database files compatible across platforms? I saved a database file in .NET Compact Framework 2.0. I move the file over to another computer that has db4o JAVA version, and it won't open it. I know my Java version is working because it can create and open a new database file made in Java fine. Why won't it open the one saved by the CF ...

I think I had a similar problem. And I believe it has to do with how Generics work in Java: The Generic method match(T) is not compiled into an actual method match(ActualClass) for a specific ActualClass. Generics can only do type checking at compile time! At Runtime, the method will not know about the actual class anymore: it will basically be ...

this is my solution...   import java.lang.reflect.Field;import java.util.List;import br.com.entrepostosilk.Empresa;import br.com.entrepostosilk.db4objects.Db4oUtil;import com.db4o.query.Predicate;public class CorretorBanco {    public static void main(String[] args) {        CorretorBanco ...

Hi I am upgrading my db4o db from version 6.3 to 7.2 but seams to get some sort for error. With my db manager I can see my objects and defragment in version 6.3 but after upgrading the Defragmentation fails (I can still browse my objects now in v. 7.2). The defragmentation gives me folloving ...

I'm having a problem storing and retrieving an object that contains a HashSet wrapped in a SynchronizedSet, e.g.: class MyClass {   private Set<UniqueID> ids = Collections.synchronizedSet(new HashSet<UniqueID>()); ... }  I can store this object and retrieve it and it will contain the UniqueIDs that I added to the ...

Hi I am a contributor to the google-guice community and open source java in general. We maintain integration modules between guice and several ORM frameworks. It seemed logical to have a db4objects alternative, and one of our contributors was kind enough to provide one. db4o is one of my long-time favorites, and we've had good success combining ...

Hi, I keep getting from ant output [db4o:enhance] Processing oopex.db4o7.nat.usecases.model.Person[db4o:enhance] enhance oopex.db4o7.nat.usecases.model.Person: skipped when trying to enhance my model classes at build time. What am I doing wrong? My environment is java 5, db4o-7.2, ant-1.7.0

Edwin, Thanks for your reply and suggestions. I will look more closely in the reference documents... I also tried to incorporate your Configuration suggestions. My server code now reads:             Configuration config = Db4o.newConfiguration();           ...

i am trying to run my first program on db4o but got stuck, i have made a package with Util.java, pilot.java and sumit.java I am getting errorrs while compiling sumit.java and here is the code [code] package a;import java.io.File;import com.db4o.Db4o;import com.db4o.ObjectContainer;import com.db4o.ObjectSet;import a.Util;    ...