Trying to run "hello world" JPA app with Maven: No Persistence provider for EntityManager

[Anton Reshetnikov]

Hello,

I'm learning JEE6 and Maven. I'm trying to resolve this issue for two days already with no success, so maybe someone could help me here? The thing is, I can't run a hello world app, that uses JPA. Here's what I do and what I get:

mvn compile

Build successful, no issues. Then:

mvn exec:java -Dexec.mainClass="ru.hatchery.jeetest.App"

[INFO] Scanning for projects...
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building jeetest 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] >>> exec-maven-plugin:1.2.1:java (default-cli) @ jeetest >>>
[INFO] 
[INFO] <<< exec-maven-plugin:1.2.1:java (default-cli) @ jeetest <<<
[INFO] 
[INFO] --- exec-maven-plugin:1.2.1:java (default-cli) @ jeetest ---
[WARNING] 
java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:601)
    at org.codehaus.mojo.exec.ExecJavaMojo$1.run(ExecJavaMojo.java:297)
    at java.lang.Thread.run(Thread.java:722)
Caused by: javax.persistence.PersistenceException: No Persistence provider for EntityManager named jeetest
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:84)
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:54)
    at ru.hatchery.jeetest.App.main(App.java:16)
    ... 6 more
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 3.580s
[INFO] Finished at: Tue Dec 11 14:17:24 MSK 2012
[INFO] Final Memory: 8M/109M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.codehaus.mojo:exec-maven-plugin:1.2.1:java (default-cli) on project jeetest:
[ERROR] An exception occured while executing the Java class. null:
[ERROR] InvocationTargetException: No Persistence provider for EntityManager named jeetest -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

Note the message "No Persistence provider for EntityManager named jeetest" at line 22. The persistence.xml file is located in my src/main/resources/META-INF and it's being correctly copied by Maven to target/classes/META-INF. Here is the persistence.xml:

<?xml version="1.0" encoding="UTF-8"?> <persistence 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" version="2.0"> <persistence-unit name="jeetest" transaction-type="RESOURCE_LOCAL"> <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider> <class>ru.hatchery.jeetest.Book</class> <properties> <property name="eclipselink.target-database" value="DERBY"/> <property name="eclipselink.ddl-generation" value="create-tables"/> <property name="eclipselink.logging.level" value="INFO"/> <property name="javax.persistence.jdbc.driver" value="org.apache.derby.jdbc.ClientDriver"/> <property name="javax.persistence.jdbc.url" value="jdbc:derby://localhost:1527/jeetestdb;create=true"/> <property name="javax.persistence.jdbc.user" value="test"/> <property name="javax.persistence.jdbc.password" value="test"/> </properties> </persistence-unit> </persistence>

The database is also up and running. And here is the pom.xml:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>ru.hatchery</groupId> <artifactId>jeetest</artifactId> <version>1.0-SNAPSHOT</version> <packaging>jar</packaging> <name>jeetest</name> <repositories> <repository> <id>EclipseLink</id> <url>http://download.eclipse.org/rt/eclipselink/maven.repo</url> </repository> <repository> <id>DerbyClient</id> <url>http://repository.apache.org/content/repositories/releases</url> </repository> </repositories> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> </properties> <dependencies> <dependency> <groupId>org.eclipse.persistence</groupId> <artifactId>javax.persistence</artifactId> <version>2.0.0</version> </dependency> <dependency> <groupId>org.eclipse.persistence</groupId> <artifactId>eclipselink</artifactId> <version>2.0.0</version> </dependency> <dependency> <groupId>org.apache.derby</groupId> <artifactId>derbyclient</artifactId> <version>10.6.1.0</version> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.11</version> <scope>test</scope> </dependency> </dependencies> </project>

Maybe I should add a dependency for that org.eclipse.persistence.jpa.PersistenceProvider? But I don't know the groupId, artifactId and version for it. I guess my mistake is stupid, but I'm stuck on it. Please, give me a clue.

Thank you!

[Anton Reshetnikov]

Oh, yes. And this the line where the exception occurs in my java code:

EntityManagerFactory emf = Persistence.createEntityManagerFactory("jeetest");

Still have no idea what am I doing wrong. When I use 'maven exec', does it automatically include dependecy jars from the pom.xml to the java CLASSPATH?

[Danil TuchkoFf]

Probably, maven not downloaded dependencies. You need EclipseLink runtime(persistence provider), that defined in the eclipselink artifactId, you have it in pom.xml. First, remove <repository>with id eclipselink. add the following in pom.xml
<build> <finalName>NAME_OF_JAR_FILE</finalName> <plugins> <plugin> <artifactId>maven-assembly-plugin</artifactId> <configuration> <descriptorRefs> <descriptorRef>jar-with-dependencies</descriptorRef> </descriptorRefs> <archive> <manifest> <mainClass>your.main.class</mainClass> </manifest> </archive> </configuration> </plugin> </plugins> </build>
After that, instead of mvn exec, run mvn assembly:single. This command should create complete jar file with dependencies, creates Manifest with main class. And you can see all needed dependencies in that jar, and can execute it with java -jar youjar.jar.

[Anton Reshetnikov]

Hi! Thanks a lot for your reply. I did what you told me, and here is the info I got from this investigation.
First of all, Maven fetches all the dependencies correctly, they are in my local repository. Anyway, I tried use the assembly plugin. Deleting eclipselink repository from pom.xml resulted in error while compiling, though. So I left it undeleted and compiled my code:

mvn compile

[INFO] Scanning for projects...
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building jeetest 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] --- maven-resources-plugin:2.5:resources (default-resources) @ jeetest ---
[debug] execute contextualize
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 1 resource
[INFO] 
[INFO] --- maven-compiler-plugin:2.3.2:compile (default-compile) @ jeetest ---
[INFO] Compiling 2 source files to D:\Codespace\jeeproject\jeetest\target\classes
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 3.130s
[INFO] Finished at: Thu Dec 13 13:23:46 MSK 2012
[INFO] Final Memory: 10M/109M
[INFO] ------------------------------------------------------------------------

Good. Then:

mvn assembly:single

[INFO] Scanning for projects...
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building jeetest 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] --- maven-assembly-plugin:2.2-beta-5:single (default-cli) @ jeetest ---
[INFO] META-INF/MANIFEST.MF already added, skipping
[INFO] META-INF/ already added, skipping
[INFO] about.html already added, skipping
[INFO] javax/ already added, skipping
[INFO] javax/persistence/ already added, skipping
[INFO] javax/persistence/Access.class already added, skipping
...more...
[INFO] license.html already added, skipping
[INFO] org/ already added, skipping
[INFO] org/eclipse/ already added, skipping
[INFO] org/eclipse/persistence/ already added, skipping
[INFO] readme.html already added, skipping
[INFO] META-INF/ already added, skipping
[INFO] META-INF/MANIFEST.MF already added, skipping
[INFO] commonj/ already added, skipping
[INFO] commonj/sdo/ already added, skipping
[INFO] commonj/sdo/impl/ already added, skipping
[INFO] META-INF/eclipse.inf already added, skipping
[INFO] about.html already added, skipping
[INFO] META-INF/MANIFEST.MF already added, skipping
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 9.110s
[INFO] Finished at: Thu Dec 13 13:24:24 MSK 2012
[INFO] Final Memory: 13M/306M
[INFO] ------------------------------------------------------------------------

So now I have the jar with all dependencies included, so I run it:

java -jar jeetestWithDeps-jar-with-dependencies.jar

Exception in thread "main" javax.persistence.PersistenceException:
No Persistence provider for EntityManager named jeetest
        at javax.persistence.Persistence.createEntityManagerFactory(Unknown Source)
        at javax.persistence.Persistence.createEntityManagerFactory(Unknown Source)
        at ru.hatchery.jeetest.App.main(App.java:16)

The same error! Now it's clear that it's not a classpath or missing jars issue. May there is a mistake in persistence.xml or pom.xml? But persistence.xml gets copied to the jar by Maven! I don't know what to think.
I would be very grateful if someone points me on my mistake.