code: public String getISSN() {
      if (Journal_Type.featOkTst && ((Journal_Type)jcasType).casFeat_ISSN == null)
        jcasType.jcas.throwFeatMissing("ISSN", "de.julielab.jules.types.Journal");
      return jcasType.ll_cas.ll_getStringValue(addr, ((Journal_Type)jcasType).casFeatCode_ISSN);}
docs: getter for ISSN - gets The international standard serial number, O
  @generated
  @return value of the feature