Here is the code I am using. The first error I am getting is in line 3 which is String loginID = ""; I do put in my loginID, just took it out to post so that is not the issue.
// the parameters for the payment can be configured here
// the API Login ID and Transaction Key must be replaced with valid values
String loginID = "";
String transactionKey = "";
String amount = "5.00";
String description = "Sample Transaction";
String label = "Submit Payment"; // The is the label on the 'submit' button
String testMode = "false";
// By default, this sample code is designed to post to our test server for
// developer accounts: https://test.authorize.net/gateway/transact.dll
// for real accounts (even in test mode), please make sure that you are
// posting to: https://secure.authorize.net/gateway/transact.dll
String url = "https://secure.authorize.net/gateway/transact.dll";
// If an amount or description were posted to this page, the defaults are overidden
if ( request.getParameter("amount") != null )
{ amount = request.getParameter("amount"); }
if ( request.getParameter("description") != null )
{ description = request.getParameter("description"); }
// an invoice is generated using the date and time
Date myDate = new Date();
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyyMMddHHmmss");
String invoice = dateFormat.format(myDate);
// a sequence number is randomly generated
Random generator = new Random();
int sequence = generator.nextInt(1000);
// a timestamp is generated
long timeStamp = System.currentTimeMillis()/1000;
//This section uses Java Cryptography functions to generate a fingerprint
// First, the Transaction key is converted to a "SecretKey" object
KeyGenerator kg = KeyGenerator.getInstance("HmacMD5");
SecretKey key = new SecretKeySpec(transactionKey.getBytes(), "HmacMD5");
// A MAC object is created to generate the hash using the HmacMD5 algorithm
Mac mac = Mac.getInstance("HmacMD5");
mac.init(key);
String inputstring = loginID + "^" + sequence + "^" + timeStamp + "^" + amount + "^";
byte[] result = mac.doFinal(inputstring.getBytes());
// Convert the result from byte[] to hexadecimal format
StringBuffer strbuf = new StringBuffer(result.length * 2);
for(int i=0; i< result.length; i++)
{
if(((int) result[i] & 0xff) < 0x10)
strbuf.append("0");
strbuf.append(Long.toString((int) result[i] & 0xff, 16));
}
String fingerprint = strbuf.toString();
// end of fingerprint generation
// Print the Amount and Description to the screen.
out.println ("Amount: " + amount + " <br />");
out.println ("Description: " + description + "<br />");
// Create the HTML form containing necessary SIM post values
out.println ("<FORM method='post' action='" + url + "' >");
