1.  build.xml

    <target name="reversemapping"
        description="Generate java files from the database schema">
        <!-- now run the tool to generate java files from the db schema -->
        <taskdef name="reversemappingtool" classpathref="classpath"
            classname="org.apache.openjpa.jdbc.ant.ReverseMappingToolTask"/>
        <reversemappingtool
            package="com.project.domain"
            directory="build"
            generateannotations="true"
            accesstype="property"
            metadata="none"
            nullableasobject="true"
            usegenericcollections="true"
            customizerproperties="conf/reverse-customizer.properties">
            <config connectiondrivername="${dbdriver}" connectionurl="${dburl}"
                connectionusername="${dbuser}" connectionpassword="${dbpass}"
                propertiesFile="conf/persistence.xml" />
            <codeformat tabSpaces="4" spaceBeforeParen="false"
                braceOnSameLine="true"/>
        </reversemappingtool>


2.  conf/reverse-customizer.properties

reversemapping.Airlines.rename: reversemapping.Airline
reversemapping.Airline.airline.rename: airlineCode
reversemapping.Airline.airlineFull.rename: fullName
reversemapping.Cities.rename: reversemapping.City
reversemapping.Countries.rename: reversemapping.Country
reversemapping.Flightavailability.rename: reversemapping.Availability
reversemapping.Availability.identity: Availability$ID
reversemapping.Flights.rename: reversemapping.Flight
reversemapping.Flight.identity: Flight$ID
reversemapping.Flight.departTime.rename: departureTime
reversemapping.Flight.arriveTime.rename: arrivalTime
reversemapping.Flight.availabilitys.rename: availabilities
reversemapping.Country.citys.rename: cities


3.  conf/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"
    version="1.0">
    <persistence-unit name="HLSJPA" transaction-type="RESOURCE_LOCAL">
         <class>com.project.domain.Country</class>
    </persistence-unit>   
   
</persistence>