java - Hive GenericUDF return array<String> Error -

im new genericudf. i'm try generate function create telephone numbers use of array<strings>.

but have error:

caused by: java.lang.classcastexception: org.apache.hadoop.hive.serde2.lazy.lazystring cannot cast java.lang.string

in line:

string inumber = (string) listoi.getlistelement(args[1].get(), i);

could me, please? thanks.

this code:

@description(name = "create_numbers", value = "_funct_(prefix, array(number1, number2, ...)); first argument prefix(string) , second argument array of strings."         + "return list of phone numbers. "         + "example: prefix = +49 , arraynumbers = array[1234, 2346, 1356] - result: array[+491234, +492346, +491356].")  public class udfgenericlistnumbers extends genericudf { listobjectinspector     listoi; stringobjectinspector   elemoi;  public object evaluate(deferredobject[] args) throws hiveexception {              // must have 2 arguments     if(args==null || args.length != 2) {             throw new hiveexception("received " + (args == null? "null" :             integer.tostring(args.length) + " elements instead of 2"));     }      string prefix = elemoi.getprimitivejavaobject(args[0].get());      //if of them null, return null     if(args[0] == null || args[1] == null){         return null;     }      list<string> resultlnumerbs = new arraylist<string>();           int numelem = listoi.getlistlength(args[1].get());      for(int i=0; i<numelem; i++){                    string inumber = (string) listoi.getlistelement(args[1].get(), i);                   resultlnumerbs.add(prefix + inumber);            }                  return resultlnumerbs; }  public objectinspector initialize(objectinspector[] args) throws udfargumentexception {      // check number of arguments. accept 2     if (args.length != 2) {           throw new udfargumentlengthexception("two arguments needed: string , list<string>, found "+ args.length);     }      //check received right objects types.     if (!(args[0] instanceof stringobjectinspector) || !(args[1] instanceof listobjectinspector)) {       throw new udfargumentexception("first argument must string , second argument must list / array of string");     }      this.elemoi = (stringobjectinspector) args[0];     this.listoi = (listobjectinspector) args[1];      //check list contains strings     if(!(listoi.getlistelementobjectinspector() instanceof stringobjectinspector)) {       throw new udfargumentexception("second argument must list of strings");     }      // return type of our function array of string, provide correct object inspector             return (stringobjectinspector)listoi.getlistelementobjectinspector(); }  @override public string getdisplaystring(string[] arg0) {     return "create_numbers"; }  } 

instead of

string inumber = (string) listoi.getlistelement(args[1].get(), i);  

try

string inumber =  listoi.getlistelement(args[1].get(), i).tostring(); 

since getlistelement() return object should castable.