Using a Servlet doPost method

Using a Servlet doPost method

Im new to Java and trying out some financial analysis java file I'm using
for my studies. I got it to work when I created a main method within the
bean itself. However when I try to pass the values needed through a jsp
form and using a servlet doPost method to do the calculations by
instantiating the methods from the bean nothing happens I get a
NullPointerException. Im assuming the BlackScholes.java works as a bean
should and that the issue is within the code presented. Help here would be
greatly appreciated.
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException,IOException {
String action = request.getParameter("action");
if (action != null) {
try {
String spotPrice = request.getParameter("sprice");
String strikePrice = request.getParameter("strike");
String interestRate = request.getParameter("rate");
String timeTo = request.getParameter("time");
String vol = request.getParameter("volatility");
double sprice = Double.parseDouble(spotPrice);
double strike = Double.parseDouble(strikePrice);
double rate = Double.parseDouble(interestRate);
double time = Double.parseDouble(timeTo);
double volatility = Double.parseDouble(vol);
double carryrate = rate;
request.setAttribute("sprice", sprice);
request.setAttribute("strike", strike);
request.setAttribute("rate", rate);
request.setAttribute("time", time);
request.setAttribute("volatility", volatility);
BlackScholes BS = new BlackScholes(carryrate);
BS.bscholEprice(sprice, strike, volatility, time, rate);
double currentpriceC = BS.getCalle();
request.setAttribute("validation1", currentpriceC);
} catch (NullPointerException e) {
return;
}
} else {
request.getRequestDispatcher("/index.jsp").forward(request,
response);
}
}
}
The jsp file used to creat the form data:
<form action="${pageContext.request.contextPath}/OptionsController"
method="post">
<input type="hidden" name="action" value="docalculate" />
Spot Price: <input type="text" name="sprice" /> <br />
<p />
Strike Price: <input type="text" name="strike" /> <br />
<p />
Risk Free Rate: <input type="text" name="rate" /> <br />
<p />
Months To Expire: <input type="text" name="time" /> <br />
<p />
Volatility: <input type="text" name="volatility" /> <br />
<p />
<input type="submit" value="Submit" /><br />
<p />
One call options costs: <input type="text" name="validation1"
readonly="readonly"
value="<%if (request.getAttribute("validation1") != null) {
out.print(request.getAttribute("validation1"));
}%>">
</form>