data get property problem

I am trying very simple thing to get the property of the model, but somehow it doesn't work. Can anyone help? actually i tried many thing but every thing didn't work..

oModel.read("MD_HEADSet(BUKRS='"+BUKRS+"',LIFNR='"+key+"',KUNNR='',USRID='03101188',UTYPE='33')/?$expand=MD_ZLSCHSet,MD_BANKSet,MD_RECONSet",null,null,true,function(oData,repsonse){

        oJsonModel.setData(oData);

         });

         console.log(oJsonModel);

         var FAVORITE = oJsonModel.getProperty("/FAVORITE");

         console.log(FAVORITE);

console say to me undefined