<repository>
    <id>jboss-repo</id>
    <url>https://repository.jboss.org/nexus/content/groups/public/</url>
</repository>

<dependency>
    <groupId>org.codehaus.btm</groupId>
    <artifactId>btm</artifactId>
    <version>2.1.1</version>
</dependency>

<dependency>
    <!-- ORCL can't be bothered to update javax.persistence in Maven central but
         I hear great things about their new sailboat -->
    <groupId>org.hibernate.javax.persistence</groupId>
    <artifactId>hibernate-jpa-2.0-api</artifactId>
    <version>1.0.1.Final</version>
</dependency>

<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-entitymanager</artifactId>
    <version>3.6.6.Final</version>
    <exclusions>
        <!-- Javassist does the job -->
        <exclusion>
            <groupId>cglib</groupId>
            <artifactId>cglib</artifactId>
        </exclusion>
    </exclusions>
</dependency>

java.naming.factory.initial=bitronix.tm.jndi.BitronixInitialContextFactory

// Each JVM needs a stable unique identifier for TX recovery
TransactionManagerServices.getConfiguration().setServerId("myServer1234");

// Create the datasource and set the connection pool details
PoolingDataSource datasource = new PoolingDataSource();
datasource.setUniqueName("myDS");
datasource.setMinPoolSize(5);
datasource.setMaxPoolSize(25);
datasource.setPreparedStatementCacheSize(50);

// If you use Hibernate's hbm2ddl.auto mode, on startup SchemaExport executes
// connection.setAutoCommit(true) to export DDL. This is a non-XA transaction.
// Alternatively, wrap UserTransaction.begin() and commit() around your Hibernate
// startup code.
datasource.setAllowLocalTransactions(true);

// This is for H2 DBMS, which I really like for small scale use
datasource.setClassName("org.h2.jdbcx.JdbcDataSource");
datasource.getDriverProperties().put("URL", "jdbc:h2:mem:myTemporaryDB");
// H2 doesn't need a password for temporary in-memory databases
//datasource.getDriverProperties().setProperty("user", "scott");
//datasource.getDriverProperties().setProperty("password", "tiger");

// Create pool, bind datasource to JNDI
datasource.init();

<persistence 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"
             version="2.0">

    <persistence-unit name="myPU">
        <jta-data-source>myDS</jta-data-source>
        <properties>

            <property name="hibernate.dialect"
                      value="org.hibernate.dialect.H2Dialect"/>

            <property name="hibernate.transaction.manager_lookup_class"
                      value="org.hibernate.transaction.BTMTransactionManagerLookup"/>

            <property name="hibernate.hbm2ddl.auto"
                      value="create"/>

        </properties>
    </persistence-unit>

</persistence>

Context ctx = new InitialContext();
EntityManagerFactory emf = Persistence.createEntityManagerFactory("myPU");

UserTransaction tx = (UserTransaction) ctx.lookup("java:comp/UserTransaction");
tx.begin();

EntityManager em = emf.createEntityManager();
em.persist();
em.createQuery();

tx.commit();