List() in java.io.file

Question

Hallo everybody!
Can someone solve a little problem for me?
I want to list files and directories in a directory. If one of the files is a dirctory I want to put an "/" to the end of it. I works well if I list the current directory but not if I try to list a path like c:\temp.
Here is my code :
public class Lista {
//int i;
int i = 0;
//File Katalog;
// constructors
public Lista() {
usage();
public Lista(String[] l_files) {
list_files(l_files);
// methods
// method called if 1 argument is passed to main
private void list_files(String[] lf) {
// first check if katalog is a file
File katalog = new File(lf[0]);
// String c = new String(lf[1]);
if (katalog.isFile()) {
System.out.println(katalog + " is a file");
System.exit(1);
// check if katalog exists
if (katalog.exists()) {
String[] en_lista = katalog.list();
while (i < en_lista.length) {
File f = new File(en_lista);
if (f.isDirectory() == true) {
//if (f.isFile()) {
//f.getParent();
System.out.println(f + "/");
else {
System.out.println(f);
i++;
else
System.out.println(katalog + " doesn't exist");
// method called if no or more than 1 argument are passed to main
private void usage() {
System.out.println("\nusage : " + "\njava Lista directory");
System.exit(0);
public static void main(String[] args) {
// depending on the number of arguments passed to main different constructors are called
if (args.length < 1 || args.length > 2) {
new Lista();
else if (args.length == 1) {
new Lista(args);

Answer 1

**** example 1 ******
Here it works as I want it to do
java Lista . givs the output
directory/ (the slash mark that it is a directory)
Lista.class
Lista.java
**** example 2 ******
If I list like below it doesn't work
java Lista c:\temp givs the output
directory
file.txt
(I want to have the slash in the end of the directory to mark it's a directory but it doesn't)