OpenJPA with Oracle - NullPointerException while creating the EntityManager - jpa

Question

I am new to OpenJPA. When I tried to write a sample program with OpenJPA and Oracle, I am getting a NullPointerException while creating the EntityManager.
Sample program is
public static void main(String[] args) {
EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory("testjpa");
EntityManager em = entityManagerFactory.createEntityManager();
EntityTransaction userTransaction = em.getTransaction();
userTransaction.begin();
Customer customer = new Customer();
customer.setFirstName("Charles");
customer.setLastName("Dickens");
customer.setCustType("RETAIL");
customer.setStreet("10 Downing Street");
customer.setAppt("1");
customer.setCity("NewYork");
customer.setZipCode("12345");
em.persist(customer);
userTransaction.commit();
em.close();
entityManagerFactory.close();
}
persistence.xml is
<persistence-unit name="testjpa">
<provider>
org.apache.openjpa.persistence.PersistenceProviderImpl
</provider>
<class>sample.jpa.entity.Customer</class>
<properties>
<property name="openjpa.jdbc.DBDictionary" value="oracle(DriverVendor=oracle)" />
<property name="openjpa.ConnectionURL" value="jdbc:oracle:thin:#localhost:1521:xe" />
<property name="openjpa.ConnectionDriverName" value="oracle.jdbc.driver.OracleDriver" />
<property name="openjpa.ConnectionUserName" value="xxxxx" />
<property name="openjpa.ConnectionPassword" value="xxxxx" />
<property name="openjpa.Log" value="SQL=TRACE" />
</properties>
</persistence-unit>
Stacktrace is
Exception in thread "main" java.lang.NullPointerException
at sample.jpa.main.TestJPA.main(TestJPA.java:16)
This is happening at
EntityManager em = entityManagerFactory.createEntityManager();
Can anyone help me to resolve this?

Answer 1

Like Eelke told you already: You have to post the exact stack trace. There is no chance to start debugging this without the stack.
I also hope that his whitespace behind "Persistence" in your code snippet is just a typo:
EntityManagerFactory entityManagerFactory = Persistence .createEntityManagerFactory("testjpa");
Sebastian