Sha1 hash function (Message Digest)

Question

I am trying to create a program that lists the current java programs in a directory that is run through command line arguments, ( which works) however once i have populated all the java files i need to then turn the file names into sha1 message digests for the next step. I have the relevant code for this to work but i can not get it to compile is there something i have done wrong? or put the code in the wrong place?? here is my code feel free to amend it.
Thanks Mich
import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.io.File;
import java.io.FilenameFilter;
import java.util.Scanner;
public class ListDirectories implements FilenameFilter {
static Scanner sc = new Scanner(System.in);
public static void main (String [] args) throws UnsupportedEncodingException, NoSuchAlgorithmException {
String path = args [0];
ListDirectories ff = new ListDirectories();
ff.process(path);
public void process(String dir) {
String objects[] = (new File(dir)).list(this);
for (int i = 0; i < objects.length; i++) {
System.out.println("TRACE:"+objects);
public boolean accept(File dir, String s) {
if (s.endsWith(".java")) {
return true;
return false;
//public void MessageDigest(){
MessageDigest md = MessageDigest.getInstance("SHA");
try {
md.update(objects);
MessageDigest objects = md.clone();
byte[] objectsDigest = objects.digest();
md.update(objects);
} catch (CloneNotSupportedException cnse) {
throw new DigestException("couldn't make digest of partial content");

Answer 1

import java.io.UnsupportedEncodingException;
import java.security.DigestException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.io.File;
import java.io.FilenameFilter;
import java.util.Scanner;
public class ListDirectories implements FilenameFilter {
     static Scanner sc = new Scanner(System.in);
     public static void main (String [] args) throws UnsupportedEncodingException, NoSuchAlgorithmException {
          String path = args [0];
          ListDirectories ff = new ListDirectories();
          ff.process(path);
     public void process(String dir) {
          String objects[] = (new File(dir)).list(this);
          for (int i = 0; i < objects.length; i++) {
               System.out.println("TRACE:"+objects);
     public boolean accept(File dir, String s) {
          if (s.endsWith(".java")) {
               return true;
          return false;
     public void MessageDigest(){
          MessageDigest md = MessageDigest.getInstance("SHA");
          try {
               MessageDigest objects = md.clone();
               md.update(objects);
               byte[] objectsDigest = objects.digest();
               md.update(objects);
          } catch (CloneNotSupportedException cnse) {
               throw new DigestException("couldn't make digest of partial content");
}this where the error occur
MessageDigest objects = md.clone();
md.update(objects);
byte[] objectsDigest = objects.digest();
md.update(objects);
The method update(byte) in the type MessageDigest is not applicable for the argumentsListDirectories.java     line 42     1187874400500     26683
The method update(byte) in the type MessageDigest is not applicable for the arguments ListDirectories.java     line 44     1187874400500     26684
Type mismatch: cannot convert from Object to MessageDigest     Test2     ListDirectories.java     line 41     1187874400500     26682