can't create jpa tables in eclipse

Question

I had a working project in eclipse which created a JPA table from entity to mysql database (still learning). Unfortunately it made the table in the wrong database as I wanted there to be 'test' and 'production' databases. Somehow it got the details for the 'production' db, even that it looked like the selected database connection was for the test. I tampered with the project a bit and made it to connect with right connection object for certain (test). I can ping the db in eclipse (both dbs) and see the db in the Data Source Explorer. But now I can not create the table(s) for the project by right clicking on it and selecting 'JPA 'Tools' > 'Generate Tables from Entities'. The creation starts and finishes with no errors, like everything works, yet I see no tables in either of the databases. (In eclipse Database explorer or from command line). The persistence.xml should be fine as it already created that one table before.

The only error is for the Entity class as it says for the Entity annotation "Table xxx cannot be resolved". And as I see, it's coming from the table not being created.

Here's the persistence.xml just in case. http://pastebin.com/djPZei90

The project is also a Maven project and it uses SVN. The dependencies were successfully loaded by the maven for the eclipse/project and there is no complications with the SVN.

Because of Maven there are 2 persistence.xml files (only the login credentials and the database name changes), for production and test. It could be that the db-connection was checked and loaded from the wrong file at the 1st place. (just guessing)

Also I tried to create the script.sql when generating the table(s). I found the file but it was completely empty.

Anyway the problem is now that I can't create the tables anywhere. I am totally puzzled by this. Any hints where I should look to fix this?

Answer 1

Chris had it right, even that I didn't understand the answer correctly at the first reading. I tried with the other provider, but I may had modified the wrong file by accident (2 'persistence.xml' files as it's a maven project), or there may have been some other reason I failed to spot. I was given a hint earlier, that I should use the given provider (in persitence.xml). Causing that I didn't pay too much attention to it after all. Since using eclipselink, the provider has to be indeed:

    <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>

Thanks again Chris, even that I failed at the first attempt and had to spend several more hours on resolving this.

Answer 2

Could you solve the problem? Unfortunately I have stumbled on the same rare issue, which totally makes no sense. The JPA Tools just doesn't add the mapping classes for whatever reason, although it writes them into the persistence.xml.

Previous week everything worked flawlessly but now everything is f**. I even created a new independent project in different workspace but it happens the same bug. Obviously it's an eclipse/plugin bug, otherwise I can't explain it. Working with eclipse 4.2.0. I am not happy.

Edit: After removing Dali Tools, JPA Configurator, Seam 3 Plugin creating entities seems to work again. Don't know why, most likely a conflict, but it still doesn't explain why it happened now and not 1 month ago. I didn't change my eclipse install at all since then...

Answer 3

Spend the whole day on this.

I created a completely new (JPA) project in Eclipse (Indigo btw). Also created a new database (mysql) for that.

Made a connection in Eclipse for that. File > New > Other... > Connection Profile.

Made a new package structure and let the Eclipse create the 'persistence.xml' (src/META-INF/persistence.xml).

I made an 'JPA Entity' class with eclipse wizard. (added 'id' (PK) and 'content' fields) Copied the 'pom.xml' from my previous project to the new one (made only minor changes like the project name).

Also copied the 'persistence.xml' file from the previous project (src/main/java/META-INF/, no 'test' included). Changed database details and login credentials from the persistence file.

Made the project 'Maven project' in eclipse (right click on project name > Configure) As it was now a Maven project the default 'persistence.xml' could be removed as it was in wrong place. (Mavenizing the project removed all the errors from un-existing jars with the pom.xml)

Tried to create the table again for the project (Same error, but wait...).

Right clicked on project > Maven > Disable Maven Nature

Then again made it maven project, right clicked on project > Configure > ...

Tried creating the tables again and it created them. Everything works!

Go figure!

Seems like everything was ok, like I suspected. There seems to be some sort of bug with maven (plugin) + eclipse.

Doing the same tricks on the previous project won't help. I even created the entity class with the wizard (removed the existing). The <class> declaration is added to the 'persistence.xml', but it still wont do the table. (Also tried removing and re-adding the maven nature)

I could be missing something on the process/did it differently or doing it wrong whole together. But considering I get the other project work while other doesn't, using the same tricks, there seems to be a big nasty bug.