Java Utililty Methods MD5 File

if (file == null || file.isDirectory() || !file.exists())
    return null;
MessageDigest md5Checker;
try {
    md5Checker = MessageDigest.getInstance("MD5"); 
} catch (NoSuchAlgorithmException e) {
    return null;
InputStream fis = null;
try {
    fis = new BufferedInputStream(new FileInputStream(file));
    int read = -1;
    while ((read = fis.read()) != -1) {
        md5Checker.update((byte) read);
    byte[] digest = md5Checker.digest();
    StringBuffer buf = new StringBuffer();
    for (int i = 0; i < digest.length; i++) {
        if ((digest[i] & 0xFF) < 0x10)
            buf.append('0');
        buf.append(Integer.toHexString(digest[i] & 0xFF));
    return buf.toString();
} catch (FileNotFoundException e) {
    return null;
} catch (IOException e) {
    return null;
} finally {
    if (fis != null)
        try {
            fis.close();
        } catch (IOException e) {

if (file == null) {
    throw new IOException("Can't compute MD5 without a File.");
if (!file.isFile()) {
    throw new IOException("Can't compute MD5, because \"" + file + "\" is not an existing file.");
return computeMD5(new FileInputStream(file));

return computeMD5(file, MD5_BUFFER_LENGTH);

MessageDigest md = MessageDigest.getInstance("MD5");
FileInputStream ifs = new FileInputStream(filename);
ByteArrayOutputStream byteOutput = null;
StringBuffer hexString = new StringBuffer();
byte[] bytes = new byte[1024];
int read;
byteOutput = new ByteArrayOutputStream();
while ((read = ifs.read(bytes)) > -1)
...

try (final FileInputStream fis = new FileInputStream(file)) {
    return computeMd5Digest(fis);

if (file == null) {
    throw new NullPointerException("The file argument is null");
return computeMD5Sum(new FileInputStream(file));