Step 2: Creating a persistence unit

A persistence unit in is named scope where we define persistence contextual details such as data source information, a list of entities to include (or exclude), and any other information that may be useful for the persistence provider to work. A persistence unit is identified by a unit name, and is created by defining the following file:

/META-INF/persistence.xml 
<?xml version="1.0" encoding="UTF-8"?> 
<persistence version="2.1" xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd"> 
  <persistence-unit name="jpa-examplesPU" transaction-type="JTA"> 
    <jta-data-source>java:app/cinemasapp-ds</jta-data-source> 
    <exclude-unlisted-classes>false</exclude-unlisted-classes> 
    <properties> 
      <property name="javax.persistence.schema-generation.database.action" value="create"/> 
    </properties>

  </persistence-unit> 
</persistence>