Or use

    // get the frozen state is only one of 0,1,2 
            IF (StringUtils.notBlank (frozenStatus)) {
                 IF (( "0" .equals (frozenStatus) || "1" .equals (frozenStatus)! | | "2" .equals (frozenStatus))) { 
                    errmsgSb.append ( "frozen state parameter value is not valid;" );
                     // missing parameters 
                    returnJson.put ( "The errcode", "3002" ); 
                    checkFlag = to false ;     
                } 
            }