Java MD5 Copy function generates different digest

I am experimenting with Java and created a small program that copies a file and generates a MD5 checksum. The program works and generates a checksum, but the resulting file that is copied does not match the original checksum.

I am new to Java and do not understand what the problem is here. Am I writing the wrong buffer to the output file?

package com.application;

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.math.BigInteger;
import java.security.MessageDigest;

public class Main {

    static int secure_copy(String src, String dest) throws Exception {
        InputStream inFile = new FileInputStream(src);
        OutputStream outFile = new FileOutputStream(dest);
        MessageDigest md = MessageDigest.getInstance("MD5");
        byte[] buf = new byte[1024];
        int numRead;

        do {
            numRead = inFile.read(buf);
            if (numRead > 0) {
                md.update(buf, 0, numRead);
                outFile.write(buf);
                outFile.flush();
            }
        } while (numRead != -1);

        inFile.close();
        outFile.close();

        BigInteger no = new BigInteger(1, md.digest());
        String result = no.toString(16);
        while(result.length() < 32) {
            result = "0" + result;
        }

        System.out.println("MD5: " + result);
        return 0;
    }

    public static void main(String[] args) {
        try {
            secure_copy(args[0], args[1]);
        } catch (Exception e) {
            System.out.println("Error: " + e.getMessage());
        }
    }
}

Output from source file: (Correct)

MD5: 503ea121d2bc6f1a2ede8eb47f0d13ef

The file from the copy function, checked via md5sum

md5sum file.mov 
56883109c28590c33fb31cc862619977  file.mov

You are writing the entire buffer to the output file, not just the portion that has data from the latest read. The fix is simple:

        if (numRead > 0) {
            md.update(buf, 0, numRead);
            outFile.write(buf, 0, numRead);
        }