I need to import data from tab seperated text file. Each row is one record - ArchiveTr7Record

@Entity
public class ArchiveTr7Record implements java.io.Serializable
{
...
}

I have implemented the following business method within @Stateless bean:

@Stateless
public class ArchiveTr7DAOBean implements ArchiveTr7DAO {
 @Inject private EntityManager em;

 boolean importTabSeperatedFile(String importFile)
 {
 // openning input file
 (...)
 String l = lineReader.readLine();
 while (l != null) {
 ArchiveTr7Record rec = parseRecord(l);
 if (rec!=null)
 {
 em.persist(rec);
 em.flush();
 }
 l = lineReader.readLine();
 }

 return true;
 }
}

When I execute method importTabSeperatedFile:

 ArchiveTr7DAO archiveTr7 = (ArchiveTr7DAO) ctx.lookup(ArchiveTr7DAO.class.getName());
 archiveTr7.importTabSeperatedFile( fileName );

The data are not flushed to the database within the loop, and finally the JBOSS server is OutOfMemory! How should I implement it?