resources.xml and persistence.xml

<?xml version="1.0" encoding="UTF-8"?>
<resources>
  <Resource id="jdbc/provadacance" type="javax.sql.DataSource">#Thu Oct 23 14:00:00 CEST 2014
jdbcDriver=org.apache.derby.jdbc.ClientDriver
password=app
userName=app
jdbcUrl=jdbc\:derby\://localhost\:1527/sample
jtaManaged=true
</Resource>
</resources>
---------------------------------

persistence_xml

?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" 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">
  <persistence-unit name="ptrovacancPU" transaction-type="JTA">
    <jta-data-source>jdbc/provadacance</jta-data-source>
    <exclude-unlisted-classes>false</exclude-unlisted-classes>
    <properties/>
  </persistence-unit>
</persistence>