// 40 + 50
ExprNodeGenericFuncDesc addition = new ExprNodeGenericFuncDesc(TypeInfoFactory.intTypeInfo, plus, Arrays.asList(fourty, fifty));
// cast(.... as string)
UDFToString stringCast = new UDFToString();
GenericUDFBridge stringCastBridge = new GenericUDFBridge("cast", false, stringCast.getClass().getName());
// cast (40 + 50 as string)
ExprNodeGenericFuncDesc cast = new ExprNodeGenericFuncDesc(TypeInfoFactory.stringTypeInfo,
stringCastBridge, "cast", Collections.<ExprNodeDesc> singletonList(addition));