Set children  = this.getChild_stems();
Set children  = this.getChildStemsNpHi();
  public Stem addChildStem(String extension, String displayExtension)     throws  InsufficientPrivilegeException,            StemAddException   {    StopWatch sw = new StopWatch();    sw.start();    try {      AttributeValidator.namingValue(extension);      AttributeValidator.namingValue(displayExtension);    }    catch (ModelException eM) {      throw new StemAddException(eM.getMessage(), eM);    }    PrivilegeResolver.getInstance().canSTEM(      this.getSession(), this, this.getSession().getSubject()    );    try {      StemFinder.findByName(        this.getSession(), constructName(this.getName(), extension)      );      throw new StemAddException("stem already exists");    }    catch (StemNotFoundException eSNF) {      // Stem does not exist.  This is what we want.  Now create it.      try {        _initializeChildGroupsAndStems(this);      }      catch (HibernateException eH) {        throw new StemAddException(eH.getMessage(), eH);      }      try {        Stem child = new Stem(this.getSession());        // Set naming attributes        child.setStem_extension(extension);        child.setDisplay_extension(displayExtension);        child.setStem_name(           constructName(this.getName(), extension)        );        child.setDisplay_name(           constructName(this.getDisplayName(), displayExtension)        );        // Set parent        child.setParent_stem(this);        // Add to children         Set children  = this.getChild_stems();        children.add(child);        this.setChild_stems(children);        // And save        Set objects = new LinkedHashSet();        objects.add(child);        objects.add(this);        HibernateHelper.save(objects);        sw.stop();        EventLog.info(s, M.STEM_ADD + U.q(child.getName()), sw);        _grantDefaultPrivsUponCreate(child);        return child;      }      catch (HibernateException eH) {        throw new StemAddException(          "Unable to add stem " + this.getName() + ":" + extension + ": "           + eH.getMessage(), eH        );      }    }  } // public Stem addChildStem(extension, displayExtension)