Formulas don't throw exceptions but show up "#NAME"

[Justin Flowers]

Hi everyone!

I'm a new user for this mail group so let me know if I'm making any mistakes 
here!

So I'm having some issues getting user defined functions running. I've defined 
a STDEV.P and T.TEST custom functions and attached them using:

   private static void setupCustomFormulas(Workbook wb){
      String[] functionNames = { "STDEV.P", "T.TEST" } ;
      FreeRefFunction[] functionImpls = { new STDEVP(), new TTEST() } ;
      UDFFinder udfs = new DefaultUDFFinder( functionNames, functionImpls ) ;
      UDFFinder udfToolpack = new AggregatingUDFFinder( udfs ) ;
      wb.addToolPack(udfToolpack);
   }

Here's the evaluate method of the STDEV.P class:

class STDEVP implements FreeRefFunction {
      @Override
      public ValueEval evaluate(ValueEval[] arg0, OperationEvaluationContext 
arg1)
      {
         // Pull out values in the range provided
         String firstPoint = arg0[0].toString().replace("]", 
"").split("!")[1].split(":")[0];
         String secondPoint = arg0[0].toString().replace("]", 
"").split("!")[1].split(":")[1];
         String sheetName = arg0[0].toString().split("\\[")[1].split("!")[0];

         EvaluationWorkbook wb = arg1.getWorkbook();

         EvaluationSheet sheet = wb.getSheet(wb.getSheetIndex(sheetName));
         double value = 0;

         char curCol = firstPoint.charAt(0);
         char curRow = firstPoint.charAt(1);
         char finalCol = secondPoint.charAt(0);

         ArrayList<Double> values = new ArrayList<Double>();

         while(curCol < finalCol){
            value = getNumericCellValue(sheet, Character.toString(curCol) + 
Character.toString(curRow));
            values.add(value);
            curCol++;
         }

         // Calculate standard deviation for data set and return
         return new NumberEval(getStdDev(values));
      }

Here's the TTEST evaluate method:

class TTEST implements FreeRefFunction{
   @Override
   public ValueEval evaluate(ValueEval[] arg0, OperationEvaluationContext arg1)
   {
      for(int i = 0; i < arg0.length; i++){
         System.out.println("ARGS: " + arg0[i]);
      }

      String start1 = arg0[0].toString().replace("]", 
"").split("!")[1].split(":")[0];
      String end1 = arg0[0].toString().replace("]", 
"").split("!")[1].split(":")[1];
      String start2 = arg0[1].toString().replace("]", 
"").split("!")[1].split(":")[0];
      String end2 = arg0[1].toString().replace("]", 
"").split("!")[1].split(":")[1];
      String sheetName = arg0[0].toString().split("\\[")[1].split("!")[0];

      EvaluationSheet sheet = 
arg1.getWorkbook().getSheet(arg1.getWorkbook().getSheetIndex(sheetName));

      double[] set1 = getValuesInRange(start1, end1, sheet);
      double[] set2 = getValuesInRange(start2, end2, sheet);

      TTest ttest = new TTest();

      double t_statistic = ttest.t(set1, set2);

      return new NumberEval(t_statistic);
   }

How I write the formula cells:

for(int i = 0; i < grid.length; i++){
         Row row = sheet.createRow((short)i);
         for (int j = 0; j < grid[i].length; j++){
            Cell cell = row.createCell(j);

            try{
               cell.setCellValue((Double)grid[i][j]);
            }
            catch(Exception e){
               String val = (String) grid[i][j];
               if (val != null && val.startsWith("=")){
                  val = val.replaceAll("=", "");
                  cell.setCellType(XSSFCell.CELL_TYPE_FORMULA);
                  cell.setCellFormula(val);
               }
               else{
                  cell.setCellValue(val);
               }
            }
         }
      }

So when I run my code and hit the evaluateAll() method no exceptions are thrown 
but when I open the workbook generated the default formulas are correctly 
calculated but the UDF formulas report back "#NAME?" as the value. When I click 
on the cell the contained formula is correct, though. Any ideas what I'm doing 
wrong here?

Thanks a lot!

Justin