OAF CheckBox 代碼選中

public void processRequest(OAPageContext pageContext, OAWebBean webBean)
  {
    super.processRequest(pageContext, webBean);

   OAMessageCheckBoxBean oamessagecheckboxbean = (OAMessageCheckBoxBean)pageContext.getPageLayoutBean().findIndexedChildRecursive("ChkAddlDetails");
// here ChkAddlDetails is check box item id in the page
   oamessagecheckboxbean.setDefaultValue("Y");
//   or (use only one statement whichever works fine)
   oamessagecheckboxbean.setChecked(true);
}