How can I connect to a MySQL database with JPA (Hibernate) in a GWT project?

Question

I could use JPA in a sample Java project. This is how it looked like:

I use a MySQL database. I connect to it with Hibernate 4.3.5.

The project tree:

enter image description here

I imported these .jar files: (It contains the Hibernate 4.3.5 .jar files and the mysql-connector-java-5.1.29-bin.jar)

enter image description here

This is the persistence.xml:

<?xml version="1.0" encoding="UTF-8"?>

<persistence version="2.0"
    xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">

    <persistence-unit name="DB" transaction-type="RESOURCE_LOCAL">
        <provider>org.hibernate.ejb.HibernatePersistence</provider>

        <properties>
            <property name="hibernate.show_sql" value="true" />
            <property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
            <property name="javax.persistence.jdbc.url" value="jdbc:mysql://127.0.0.1:3306/mintaalkalmazas2"/>
            <property name="javax.persistence.jdbc.user" value="root" />
            <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>
            <property name="hibernate.hbm2ddl.auto" value="update"/>
        </properties>
    </persistence-unit>
</persistence>

This is a part of a class which would I save to a table (Kerdes.java):

...
@Entity
@Table(name="kerdes")
public class Kerdes {

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private int id;

    @Column
    private int feladatlapID;

    @Column
    private String kerdes;

    @Column
    private int tipus;

    @Column
    private int sorszam;

    @Column
    private String valasz;
...

I run my application with my Main.java file. This is a part of it:

    static EntityManagerFactory emf = Persistence.createEntityManagerFactory("DB");
    static EntityManager em = emf.createEntityManager();

    public static void main(String[] args) {

        try {
            em.getTransaction().begin();

            insert();
            select();
            update();
            delete();

            em.getTransaction().commit();
        }
        catch (Exception e) {
            em.getTransaction().rollback();
            e.printStackTrace();
        }
        finally{
            emf.close();
        }

        System.out.println("It is over");
    }

And this is running fine.

I tried to make the same in a GWT application. I would connect to the same database and I want to do the same. I generated the project with sample code and I added my methods to the server.

This is the project tree:

enter image description here

I added the same jar files like before (Hibernate 4.3.5. jar files and mysql-connector jar)

enter image description here

I use the same persistence.xml file in src/META-INF.

I have the same Kerdes.java files, which is a row from the database table.

I put the database writing code in the server side file. This is a part of it:

...
    static EntityManagerFactory emf = Persistence.createEntityManagerFactory("DB");
    static EntityManager em = emf.createEntityManager();

    public GreetingServiceImpl() {

        try {
            em.getTransaction().begin();

            insert();
            select();
            update();
            delete();

            em.getTransaction().commit();
        }
        catch (Exception e) {
            em.getTransaction().rollback();
            e.printStackTrace();
        }
        finally{
            emf.close();
        }

        System.out.println("It is over");
    }
 ...

I get this error message:

WARNING: Error for /gwtjpa/greet
java.lang.ExceptionInInitializerError
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at java.lang.Class.newInstance(Unknown Source)
    at org.mortbay.jetty.servlet.Holder.newInstance(Holder.java:153)
    at org.mortbay.jetty.servlet.ServletHolder.initServlet(ServletHolder.java:428)
    at org.mortbay.jetty.servlet.ServletHolder.getServlet(ServletHolder.java:339)
    at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:487)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
    at com.google.appengine.api.socket.dev.DevSocketFilter.doFilter(DevSocketFilter.java:74)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.tools.development.ResponseRewriterFilter.doFilter(ResponseRewriterFilter.java:127)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:34)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:63)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:125)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.tools.development.DevAppServerModulesFilter.doDirectRequest(DevAppServerModulesFilter.java:366)
    at com.google.appengine.tools.development.DevAppServerModulesFilter.doDirectModuleRequest(DevAppServerModulesFilter.java:349)
    at com.google.appengine.tools.development.DevAppServerModulesFilter.doFilter(DevAppServerModulesFilter.java:116)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
    at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
    at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
    at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
    at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
    at com.google.appengine.tools.development.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:98)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:490)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at org.mortbay.jetty.Server.handle(Server.java:326)
    at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
    at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:938)
    at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:755)
    at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218)
    at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
    at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
    at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)
Caused by: javax.persistence.PersistenceException: No persistence providers available for "DB" after trying the following discovered implementations: org.datanucleus.api.jpa.PersistenceProviderImpl
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:180)
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:70)
    at com.gwtjpa.server.GreetingServiceImpl.<clinit>(GreetingServiceImpl.java:24)
    ... 43 more

aug. 08, 2014 9:02:47 DU com.google.apphosting.utils.jetty.JettyLogger warn
WARNING: Nested in java.lang.ExceptionInInitializerError:
javax.persistence.PersistenceException: No persistence providers available for "DB" after trying the following discovered implementations: org.datanucleus.api.jpa.PersistenceProviderImpl
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:180)
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:70)
    at com.gwtjpa.server.GreetingServiceImpl.<clinit>(GreetingServiceImpl.java:24)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at java.lang.Class.newInstance(Unknown Source)
    at org.mortbay.jetty.servlet.Holder.newInstance(Holder.java:153)
    at org.mortbay.jetty.servlet.ServletHolder.initServlet(ServletHolder.java:428)
    at org.mortbay.jetty.servlet.ServletHolder.getServlet(ServletHolder.java:339)
    at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:487)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166)
    at com.google.appengine.api.socket.dev.DevSocketFilter.doFilter(DevSocketFilter.java:74)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.tools.development.ResponseRewriterFilter.doFilter(ResponseRewriterFilter.java:127)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.tools.development.HeaderVerificationFilter.doFilter(HeaderVerificationFilter.java:34)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:63)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:125)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at com.google.appengine.tools.development.DevAppServerModulesFilter.doDirectRequest(DevAppServerModulesFilter.java:366)
    at com.google.appengine.tools.development.DevAppServerModulesFilter.doDirectModuleRequest(DevAppServerModulesFilter.java:349)
    at com.google.appengine.tools.development.DevAppServerModulesFilter.doFilter(DevAppServerModulesFilter.java:116)
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157)
    at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388)
    at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
    at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
    at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
    at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418)
    at com.google.appengine.tools.development.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:98)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:490)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at org.mortbay.jetty.Server.handle(Server.java:326)
    at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
    at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:938)
    at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:755)
    at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218)
    at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
    at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
    at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)

Here are both project exported to archive file:

Java project with JPA

GWT project with JPA

I think its a path problem, but not sure this is a similar issue but looks like you have hibernate jpamodelgen, jpa instead which shoudl be fine stackoverflow.com/questions/2841657/…, perhaps the javax.persistence.jar — wwright
– wwright, Commented Aug 8, 2014 at 19:52
Possibly unrelated to your current issue but I think you won't be able to connect to Hibernate in an AppEngine project. — Thomas Broyer
– Thomas Broyer, Commented Aug 17, 2014 at 10:45

wwright · Accepted Answer · 2014-08-09 01:41:42Z

1

using command jar -tvf hibernate-entitymanager-4.3.5.Final.jar 7380 Wed Apr 02 10:47:08 CDT 2014 org/hibernate/jpa/HibernatePersistenceProvider.class

?Are you missing datanucleus-api-jpa-4.0.1.jar

<persistence version="2.0"
    xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">

<persistence-unit name="DB" transaction-type="RESOURCE_LOCAL">
    <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>

edited Aug 9, 2014 at 1:41

answered Aug 8, 2014 at 20:49

wwright

3642 silver badges8 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Kroy Over a year ago

I modified the persistence.xml like you worte. I get this error now: (I copied the whole text in a .pdf) dl.dropboxusercontent.com/u/47788456/Stackoverflow/…

wwright Over a year ago

Hey I am going to back track. Edited above; if The edit does not work Copy src/Lib/hibernate-entitymanager-4.3.5.Final.jar to the war/WEB-INF/lib and try one more time.

wwright Over a year ago

Since it is complaining about STORE perhaps you are missing datanucleus-rdbms-3.1.3.jar. I downloaded the datanucleus-accessplatform-rdbms-3.1.3.zip seems you are missing some jars? If you are going to use org/datanucleus/api/jpa/PersistenceProviderImpl.class from datanucleus-api-jpa-3.1.3.jar the jars should be in war/WEB-INF/lib

Collectives™ on Stack Overflow

How can I connect to a MySQL database with JPA (Hibernate) in a GWT project?

1 Answer 1

3 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related