Andrea Andrea - 10 days ago 6
Java Question

JPA + Hibernate = No Persistence provider for EntityManager

I'm trying to setup JPA for my Maven project, using Hibernate as provider.

Structure of the project

├── META-INF
│ └── persistence.xml
├── src
| ├── main
| | └── java
| | ├── model
| | | └── Instance.java
| | └── App.java
| └── test
| └── java
| └── model
| └── AppTest.java
└── pom.xml


Content of persistence.xml

<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence" version="2.1">
<persistence-unit name="testjpa" transaction-type="RESOURCE_LOCAL">
<provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
<class>it.vitrociset.model.Instance</class>
<properties>
<property name="hibernate.connection.url" value="jdbc:postgresql://localhost:5432/aquasystem"/>
<property name="hibernate.connection.driver_class" value="org.postgresql.Driver"/>
<property name="hibernate.connection.username" value="username"/>
<property name="hibernate.connection.password" value="password"/>
</properties>
</persistence-unit>
</persistence>


Content of Instance.java

package model;

import javax.persistence.Entity;
import javax.persistence.Id;

@Entity
public class Instance {

@Id
private String id;
private String path;

public String getId() {
return id;
}

public void setId(String id) {
this.id = id;
}

public String getPath() {
return path;
}

public void setPath(String path) {
this.path = path;
}

}


Content of App.java

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import javax.persistence.Persistence;

public class App {
public static void main( String[] args ) {
EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory("testjpa");
EntityManager em = entityManagerFactory.createEntityManager();
EntityTransaction userTransaction = em.getTransaction();
userTransaction.begin();
Instance instance = new Instance();
instance.setId("id");
instance.setPath("path");
em.persist(instance);
userTransaction.commit();
em.close();
entityManagerFactory.close();
}
}


Content of 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></groupId>
<artifactId></artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>jar</packaging>

<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>

<dependencies>

<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>

<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>4.3.6.Final</version>
</dependency>

<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>4.3.6.Final</version>
</dependency>

<dependency>
<groupId>org.hibernate.javax.persistence</groupId>
<artifactId>hibernate-jpa-2.0-api</artifactId>
<version>1.0.1.Final</version>
</dependency>

</dependencies>

</project>


I got the following exception:

Exception in thread "main" javax.persistence.PersistenceException: No Persistence provider for EntityManager named testjpa


but I have no idea why. What is wrong in my code? I wasn't able to find the solution.

Answer

Persistence.xml is not in resources directory and therefore not in classpath. Move META-INF directory to src/main/resources.