code: public int doStartTag() throws JspException
      {
          // verify that the parent is a CheckBoxGroup
          Tag parentTag = findAncestorWithClass(this, CheckBoxGroup.class);
          if (parentTag == null) {
              String s = Bundle.getString("Tags_CheckBoxOptionNoCheckBoxGroup");
              registerTagError(s, null);
              return SKIP_BODY;
          }
  
          CheckBoxGroup parent = (CheckBoxGroup) parentTag;
          if ((parent.getOptionsDataSource() != null && !parent.isRepeater())) {
              String s = Bundle.getString("Tags_CheckBoxOptionParentHasOptionsDataSource");
              parent.registerTagError(s, null);
              return SKIP_BODY;
          }
  
          // Do nothing until doEndTag() is called
          return EVAL_BODY_BUFFERED;
      }
docs: Process the start of this tag.
  @throws JspException if a JSP exception has occurred