Optionally Setting parameters for Oracle functions from jdbc

[Ann Sebastian]

 
Connection conn = pool.getConnection(processId);
CallableStatement stmt = conn.prepareCall("BEGIN ?:=fnGetVoucherTb(?,?);End;");
stmt.registerOutParameter(1, OracleTypes.CURSOR); //REF CURSOR
   
if(this.isVoucherTbIdNull() && this.isVoucherTbIdSet())
stmt.setInt(2,this.voucherTbId); //LINE 1
stmt.execute();

I want to ?optionally set the parameter,Sometimes voucherTbId wont have values,So line 1 will be skipped due to if condition

In that case,stmt.execute throws an error.Is there any way to do it???