code: public void execute() {
          // We can assume we have the named persistence unit and its mapping file in our classpath,
          // but we may have to allow some properties in that persistence unit to be overridden before
          // we can successfully get that persistence unit's metamodel.
          Map<String, String> properties = (configuration != null) ? configuration.getProperties() : null;
          EntityManagerFactory emf = Persistence.createEntityManagerFactory(persistenceUnitName, properties);
  
          // Now we can get the persistence unit's metamodel and export it to Querydsl query types.
          Metamodel configuration = emf.getMetamodel();
          JPADomainExporter exporter = new JPADomainExporter(namePrefix, nameSuffix, new File(targetFolder), configuration);
          try {
              exporter.execute();
              generatedFiles = exporter.getGeneratedFiles();
          } catch (IOException e) {
              throw new RuntimeException("Error in JPADomainExporter", e);
          }
      }
docs: Exports the named persistence unit's metamodel to Querydsl query types.  Expects to be
  called by Ant via name convention using a method with signature public void execute().