Can someone test a prog for me, and help reading from an exty file

Question

Okay, I have a program to calculate the Pearson product-moment correlation coefficient ( http://en.wikipedia.org/wiki/Pearson_correlation_coefficient ) from an external file that I've just written for an assignment on Monday.
I can't actually run it because I can't find a machine with Java on that works, though I can compile it. Why is a long story, but University Admin are going to feel my wrath.
I would like two things.
1) would someone be kind enough to try to run it and test it in anyway and report any bugs or inadequacies back to me. (you will need to create a text file called data.dat with some numbers in, e.g.
14.234 54.4534
376.56 432.2332
23432. 23234.23
2) How can I can the computer to ask the user to enter either a) the name of the file from system.in or b) from a popup dialogue box with a browse feature (or is that incompatible with some OSs?).
The file follows:
// Import packages
     import java.io.*; // Import all the Java input/output packages
     import java.util.StringTokenizer; // Import a utility package
class Pearsontwo
public static void main (String[] args)
     /* Define variables.
          (double any number with decimal point.
          ints take integer value) */
          double     sumx, sumy,               // sum of x and sum of y
                    sumxx, sumyy,          // sum of x squared and y squared
                    sumxy;                    // sum of products of x and y
          int n;                              // n is number of lines
     // Set name of file to be read
          String fileName = data.dat; // define the name of the file
     //     (Enhancement: use user input. This requires the use of System.in which is a bit complicated.
          //System.out.print("Please type the name of the file you wish to run the analysis on:");
          //fileName = TextIO.getInt();
     // Set things for reading external file
BufferedReader br;     // Will be used to read the file
String line;          // Will be used to hold a line read from the file
StringTokenizer st; // Will be used to break a line into separate words
          String firstWord, secondWord;     // File will be read as string type
double firstNumber, secondNumber;     // that need to be converted into numbers.
try // if an error occurs, go to the "catch" block below
// Create a buffered file reader for the file
     br = new BufferedReader (new FileReader(fileName));
// Continue to read lines whilst there is one or more left to read
                    while (br.ready())
                    {   line= br.readLine();               // Read one line of the file
                         st = new StringTokenizer(line);     // Prepare to split the line into "words"
                         // Get the first two words (invalid --> error --> catch)
                              firstWord = st.nextToken();
                              secondWord = st.nextToken();
                         // Turn words into numbers (invalid --> error --> catch)
                              firstNumber = Double.parseDouble(firstWord);
                              secondNumber = Double.parseDouble(secondWord);
                         // Add the numbers to the previously stored numbers
                              sumx = sumx + firstNumber;
                              sumy = sumy + secondNumber;
                              sumxx = sumxx + (firstNumber * firstNumber);
                              sumyy = sumyy + (secondNumber * secondNumber);
                              n = n++; add one to the value of n.
// Close the file
br.close();
// Handle any error in opening the file
               catch (Exception e)
               {   System.err.println("File input error.\nPlease amend the file " + fileName);
          //     Calcuate r in stages, variance and covariance first.
               double variancex = (sumx2 - (sumx * sumx / n)) / (n - 1);     // calculates the variance of x ...
               double variancey = (sumx2 - (sumx * sumx / n)) / (n - 1);     // ... and y
               double covariance = (sumx * sumy - sumx * sumy / n ) / (n - 1);     // and the covariance of x and y
               double r = covariance / Math.sqrt(variancex * variancey);     // and the Pearson r value
               // Printout
               System.out.print("The Pearson product-moment correlation for these data is:" );
               System.out.println ( r );
               // Also print to file ?
Cheers,
Duncan.
(Note: this is my own work by Duncan Harris at Cariff University, so I'm not plaigerising anyone other than myself if I post it here and it subsequently gets found by one of the course organisers who have given permission for this sort of thing anyway!)

Answer 1

"I can't actually run it because I can't find a machine with Java on that works, though I can compile it. Why is a long story, but University Admin are going to feel my wrath."
I'm sure they're worried.
I don't understand this. You can compile, but not run? This makes no sense at all.
Why can't you simply download the JDK from Sun and install it on a machine? You could both compile and run then.
You don't need a pop-up dialog box to get an input file name from a user. The command prompt is quite sufficient.