Hi, I documented how someone good build a small OpenJPA example: http://www.vogella.de/articles/JavaPersistenceAPI/article.html
Thank you for your support. Best regards, Lars 2008/3/12, Lars Vogel <[EMAIL PROTECTED]>: > > Hi Mike, > > thank you, I must have been blind. Indeed the OpenJPA was missing. > > Thank you very, very much and sorry for such a blind spot on my side. > > I'll write a short summery on how to set a small OpenJPA up and post it > later to this newsgroup for future reference. > > Best regards, Lars > > > 2008/3/12, Michael Dick <[EMAIL PROTECTED]>: > > > > The only thing I noticed was that you didn't have OpenJPA specified on > > the classpath. You must have it specified somewhere, unless you've imported > > all the source. > > > > I'm sorry to say that I just replied to you personally, so the users > > mailing list hasn't seen these last few replies. If you'd like to post the > > sample you're using back to [email protected], then maybe someone > > else will have better luck than I did. > > > > -Mike > > > > On Wed, Mar 12, 2008 at 3:53 PM, Lars Vogel <[EMAIL PROTECTED]> > > wrote: > > > > > Hi Mike, > > > > > > thank you. I don't see a difference to "my" setup. > > > > > > If anyone wants to look at my project I uploaded it: > > > http://www.jnerlich.de/JPAExample.zip > > > > > > Cheers, Lars > > > > > > > > > 2008/3/12, Michael Dick <[EMAIL PROTECTED]>: > > > > > > > > Hi Lars, > > > > > > > > Here's what I'm using. I don't see anything obviously wrong the ones > > > > you sent me though. > > > > > > > > -Mike > > > > > > > > On Wed, Mar 12, 2008 at 2:52 PM, Lars Vogel < > > > > [EMAIL PROTECTED]> wrote: > > > > > > > > > Hi Mike, > > > > > > > > > > I'm running it in Eclipse. Yes, please send me your .classpath and > > > > > .project files. Mine are also attached for reference. > > > > > > > > > > Best regards, Lars > > > > > > > > > > <?xml version="1.0" encoding="UTF-8"?> > > > > > <projectDescription> > > > > > <name>hellopja</name> > > > > > <comment></comment> > > > > > <projects> > > > > > </projects> > > > > > <buildSpec> > > > > > <buildCommand> > > > > > <name>org.eclipse.jdt.core.javabuilder</name> > > > > > <arguments> > > > > > </arguments> > > > > > </buildCommand> > > > > > </buildSpec> > > > > > <natures> > > > > > <nature>org.eclipse.jdt.core.javanature</nature> > > > > > </natures> > > > > > </projectDescription> > > > > > > > > > > <?xml version="1.0" encoding="UTF-8"?> > > > > > <classpath> > > > > > <classpathentry kind="src" path="src"/> > > > > > <classpathentry kind="con" path=" > > > > > org.eclipse.jdt.launching.JRE_CONTAINER"/> > > > > > <classpathentry kind="lib" path="C:/Documents and > > > > > Settings/vogella/Desktop/Documents/08_MyDocuments/15_EclipseLibs/openjpa/commons- > > > > > collections-3.2.jar"/> > > > > > <classpathentry kind="lib" path="C:/Documents and > > > > > Settings/vogella/Desktop/Documents/08_MyDocuments/15_EclipseLibs/openjpa/commons- > > > > > lang-2.1.jar"/> > > > > > <classpathentry kind="lib" path="C:/Documents and > > > > > Settings/vogella/Desktop/Documents/08_MyDocuments/15_EclipseLibs/openjpa/commons- > > > > > logging-1.0.4.jar"/> > > > > > <classpathentry kind="lib" path="C:/Documents and > > > > > Settings/vogella/Desktop/Documents/08_MyDocuments/15_EclipseLibs/openjpa/commons- > > > > > pool-1.3.jar"/> > > > > > <classpathentry kind="lib" path="C:/Documents and > > > > > Settings/vogella/Desktop/Documents/08_MyDocuments/15_EclipseLibs/openjpa/derby- > > > > > 10.2.2.0.jar"/> > > > > > <classpathentry kind="lib" path="C:/Documents and > > > > > Settings/vogella/Desktop/Documents/08_MyDocuments/15_EclipseLibs/openjpa/geronimo-jms_1.1_spec- > > > > > 1.0.1.jar"/> > > > > > <classpathentry kind="lib" path="C:/Documents and > > > > > Settings/vogella/Desktop/Documents/08_MyDocuments/15_EclipseLibs/openjpa/geronimo-jpa_3.0_spec- > > > > > 1.0.jar"/> > > > > > <classpathentry kind="lib" path="C:/Documents and > > > > > Settings/vogella/Desktop/Documents/08_MyDocuments/15_EclipseLibs/openjpa/geronimo-jta_1.1_spec- > > > > > 1.1.jar"/> > > > > > <classpathentry kind="lib" path="C:/Documents and > > > > > Settings/vogella/Desktop/Documents/08_MyDocuments/15_EclipseLibs/openjpa/serp- > > > > > 1.13.1.jar"/> > > > > > <classpathentry kind="output" path="bin"/> > > > > > </classpath> > > > > > > > > > > > > > > > 2008/3/12, Michael Dick <[EMAIL PROTECTED]>: > > > > > > > > > > > Hi Lars, > > > > > > > > > > > > How are you running the program? You mention projects so you're > > > > > > probably using either Eclipse or Netbeans. I tried something > > > > > > similar to what > > > > > > you've posted and it worked for me in Eclipse. I can send you the > > > > > > .classpath > > > > > > and .project files if that will help. > > > > > > > > > > > > -Mike > > > > > > > > > > > > On Wed, Mar 12, 2008 at 10:22 AM, Lars Vogel < > > > > > > [EMAIL PROTECTED]> wrote: > > > > > > > > > > > > > Hi Venkatesch, > > > > > > > > > > > > > > I did also modify the orginal persistence.xml so that is > > > > > > > exactly the same as > > > > > > > my example to be able to run Main.java directly without the > > > > > > > ant script. > > > > > > > > > > > > > > So in both cases I'm not using the build.xml file anymore. The > > > > > > > only > > > > > > > difference I see is that one version runs the other not. > > > > > > > > > > > > > > Best egards, Lars > > > > > > > > > > > > > > 2008/3/12, Addanki, Venkatesh <[EMAIL PROTECTED] > > > > > > > >: > > > > > > > > > > > > > > > > Lars, > > > > > > > > > > > > > > > > One obvious difference between your code and the out of box > > > > > > > sample is > > > > > > > > the way the driver class and its properties are specified. > > > > > > > build.xml vs > > > > > > > > persistence.xml. It looks like the > > > > > > > org.apache.derby.jdbc.EmbeddedDriver > > > > > > > > class from your persistence.xml is not being found or the > > > > > > > connection url > > > > > > > > is not getting through. > > > > > > > > > > > > > > > > Regards > > > > > > > > > > > > > > > > V > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -----Original Message----- > > > > > > > > From: Lars Vogel [mailto:[EMAIL PROTECTED] > > > > > > > > Sent: Wednesday, March 12, 2008 9:22 AM > > > > > > > > To: [email protected] > > > > > > > > Subject: JPA - Null pointer exception > > > > > > > > > > > > > > > > Hi, > > > > > > > > > > > > > > > > I trying to make JPA work for me. The delivered example > > > > > > > works without > > > > > > > > problems, I can also successfully modify this example. The > > > > > > > example was > > > > > > > > based on http://openjpa.apache.org/quick-start.html. > > > > > > > > > > > > > > > > But if I create a new project the Entity Manager returns > > > > > > > only a NULL > > > > > > > > value. > > > > > > > > Error: > > > > > > > > > > > > > > > > Exception in thread "main" java.lang.NullPointerException > > > > > > > > at hellojpa.Main.main(Main.java:44) > > > > > > > > > > > > > > > > > > > > > > > > I use the same files as in the working example. All jars are > > > > > > > included in > > > > > > > > the build path. I assume that the persistence.xml is not > > > > > > > found but to my > > > > > > > > knowledge the classpath is correctly maintained. The path > > > > > > > .../bin > > > > > > > > contains the directory META-INF and here the file > > > > > > > persistence.xml. > > > > > > > > > > > > > > > > Any advice? I must be missing something very simple but > > > > > > > cannot figure it > > > > > > > > out. For example coding please see below. > > > > > > > > > > > > > > > > Best regards, Lars > > > > > > > > > > > > > > > > File structure: > > > > > > > > > > > > > > > > src > > > > > > > > - hellojpa > > > > > > > > - Main.java > > > > > > > > - Message.java > > > > > > > > - META-INF > > > > > > > > - persistence.xml > > > > > > > > > > > > > > > > Same structure in the bin directory. > > > > > > > > > > > > > > > > > > > > > > > > -----------persistence.xml.............. > > > > > > > > > > > > > > > > <?xml version="1.0" encoding="UTF-8"?> > > > > > > > > <!-- > > > > > > > > Licensed to the Apache Software Foundation (ASF) under > > > > > > > one > > > > > > > > or more contributor license agreements. See the NOTICE > > > > > > > file > > > > > > > > distributed with this work for additional information > > > > > > > > regarding copyright ownership. The ASF licenses this > > > > > > > file > > > > > > > > to you under the Apache License, Version 2.0 (the > > > > > > > > "License"); you may not use this file except in > > > > > > > compliance > > > > > > > > with the License. You may obtain a copy of the License > > > > > > > at > > > > > > > > > > > > > > > > http://www.apache.org/licenses/LICENSE-2.0 > > > > > > > > > > > > > > > > Unless required by applicable law or agreed to in > > > > > > > writing, > > > > > > > > software distributed under the License is distributed on > > > > > > > an > > > > > > > > "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY > > > > > > > > KIND, either express or implied. See the License for > > > > > > > the > > > > > > > > specific language governing permissions and limitations > > > > > > > > under the License. > > > > > > > > --> > > > > > > > > <persistence xmlns="http://java.sun.com/xml/ns/persistence"; > > > > > > > > xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"; > > > > > > > version="1.0"> > > > > > > > > > > > > > > > > <!-- > > > > > > > > A persistence unit is a set of listed persistent > > > > > > > entities as > > > > > > > > well > > > > > > > > the configuration of an EntityManagerFactory. We > > > > > > > configure each > > > > > > > > example in a separate persistence-unit. > > > > > > > > --> > > > > > > > > <persistence-unit name="hellojpa" > > > > > > > > transaction-type="RESOURCE_LOCAL"> > > > > > > > > <!-- > > > > > > > > The default provider can be OpenJPA, or some > > > > > > > other product. > > > > > > > > This element is optional if OpenJPA is the only > > > > > > > JPA provider > > > > > > > > in the current classloading environment, but can > > > > > > > be > > > > > > > > specified > > > > > > > > in cases where there are multiple JPA > > > > > > > implementations > > > > > > > > available. > > > > > > > > --> > > > > > > > > > > > > > > > > <provider> > > > > > > > > > > > > > > > org.apache.openjpa.persistence.PersistenceProviderImpl > > > > > > > > </provider> > > > > > > > > > > > > > > > > > > > > > > > > <!-- We must enumerate each entity in the > > > > > > > persistence unit --> > > > > > > > > <class>hellojpa.Message</class> > > > > > > > > > > > > > > > > <properties> > > > > > > > > <property name="openjpa.ConnectionURL" > > > > > > > > > > > > > > > > > > > > > > > value="jdbc:derby:C:/DerbyDatabases/hellojpa-database5;create=true" > > > > > > > /> > > > > > > > > <property name="openjpa.ConnectionDriverName" > > > > > > > > value="org.apache.derby.jdbc.EmbeddedDriver" > > > > > > > /> > > > > > > > > <property name="openjpa.ConnectionUserName" > > > > > > > value="" /> > > > > > > > > <property name="openjpa.ConnectionPassword" > > > > > > > value="" /> > > > > > > > > > > > > > > > > <!-- > > > > > > > > Tell OpenJPA to automatically create tables > > > > > > > in the > > > > > > > > database > > > > > > > > for entities. Note that this should be > > > > > > > disabled when > > > > > > > > running against a production database, since > > > > > > > you > > > > > > > > probably > > > > > > > > don't want to be altering the schema at > > > > > > > runtime. > > > > > > > > --> > > > > > > > > <property name="openjpa.jdbc.SynchronizeMappings > > > > > > > " > > > > > > > > value="buildSchema" /> > > > > > > > > > > > > > > > > </properties> > > > > > > > > </persistence-unit> > > > > > > > > > > > > > > > > </persistence> > > > > > > > > > > > > > > > > > > > > > > > > -----------Main.java > > > > > > > > > > > > > > > > /* > > > > > > > > * Licensed to the Apache Software Foundation (ASF) under > > > > > > > one > > > > > > > > * or more contributor license agreements. See the NOTICE > > > > > > > file > > > > > > > > * distributed with this work for additional information > > > > > > > > * regarding copyright ownership. The ASF licenses this > > > > > > > file > > > > > > > > * to you under the Apache License, Version 2.0 (the > > > > > > > > * "License"); you may not use this file except in > > > > > > > compliance > > > > > > > > * with the License. You may obtain a copy of the License > > > > > > > at > > > > > > > > * > > > > > > > > * http://www.apache.org/licenses/LICENSE-2.0 > > > > > > > > * > > > > > > > > * Unless required by applicable law or agreed to in > > > > > > > writing, > > > > > > > > * software distributed under the License is distributed on > > > > > > > an > > > > > > > > * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY > > > > > > > > * KIND, either express or implied. See the License for > > > > > > > the > > > > > > > > * specific language governing permissions and limitations > > > > > > > > * under the License. > > > > > > > > */ > > > > > > > > package hellojpa; > > > > > > > > > > > > > > > > import java.util.*; > > > > > > > > import javax.persistence.*; > > > > > > > > > > > > > > > > > > > > > > > > /** > > > > > > > > * A very simple, stand-alone program that stores a new > > > > > > > entity in the > > > > > > > > * database and then performs a query to retrieve it. > > > > > > > > */ > > > > > > > > public class Main { > > > > > > > > > > > > > > > > @SuppressWarnings("unchecked") > > > > > > > > public static void main(String[] args) { > > > > > > > > System.out.println(System.getProperty(" > > > > > > > java.class.path")); > > > > > > > > // Create a new EntityManagerFactory using the > > > > > > > System > > > > > > > > properties. > > > > > > > > // The "hellojpa" name will be used to configure > > > > > > > based on the > > > > > > > > // corresponding name in the > > > > > > > META-INF/persistence.xml file > > > > > > > > EntityManagerFactory factory = Persistence. > > > > > > > > createEntityManagerFactory("hellojpa", > > > > > > > > System.getProperties()); > > > > > > > > > > > > > > > > // Create a new EntityManager from the > > > > > > > EntityManagerFactory. The > > > > > > > > // EntityManager is the main object in the > > > > > > > persistence API, and > > > > > > > > is > > > > > > > > // used to create, delete, and query objects, as > > > > > > > well as access > > > > > > > > // the current transaction > > > > > > > > EntityManager em = factory.createEntityManager(); > > > > > > > > > > > > > > > > // Begin a new local transaction so that we can > > > > > > > persist a new > > > > > > > > entity > > > > > > > > em.getTransaction().begin(); > > > > > > > > > > > > > > > > // Create and persist a new Message entity > > > > > > > > em.persist(new Message("Hello Persistence!")); > > > > > > > > > > > > > > > > // Commit the transaction, which will cause the > > > > > > > entity to > > > > > > > > // be stored in the database > > > > > > > > em.getTransaction().commit(); > > > > > > > > > > > > > > > > // It is always good practice to close the > > > > > > > EntityManager so that > > > > > > > > // resources are conserved. > > > > > > > > em.close(); > > > > > > > > > > > > > > > > // Create a fresh, new EntityManager > > > > > > > > EntityManager em2 = factory.createEntityManager(); > > > > > > > > > > > > > > > > // Perform a simple query for all the Message > > > > > > > entities > > > > > > > > Query q = em2.createQuery("select m from Message > > > > > > > m"); > > > > > > > > > > > > > > > > // Go through each of the entities and print out > > > > > > > each of their > > > > > > > > // messages, as well as the date on which it was > > > > > > > created > > > > > > > > for (Message m : (List<Message>) q.getResultList()) > > > > > > > { > > > > > > > > System.out.println(m.getMessage() > > > > > > > > + " (created on: " + m.getCreated() + ")"); > > > > > > > > } > > > > > > > > > > > > > > > > // Again, it is always good to clean up after > > > > > > > ourselves > > > > > > > > em2.close(); > > > > > > > > factory.close(); > > > > > > > > } > > > > > > > > } > > > > > > > > > > > > > > > > ----------- > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >
