“Illegal forward reference” means that you are trying to use a variable before it is defined.
In this case, you are trying to invoke a method on wb in the declaration of wb.
Workbook wb = wb.getWorkbook(...);
“Illegal forward reference” means that you are trying to use a variable before it is defined.
In this case, you are trying to invoke a method on wb in the declaration of wb.
Workbook wb = wb.getWorkbook(...);