Why throws ArrayIndexOutOfBoundsException?

Question

Java

I connect to the server to select a fresh file, but when searching for a file, it throws an exception:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: Index 0 out of bounds for length 0

What could be the problem?

code snippet:

public static FTPFile lastFileModified(FTPFile[] files)
    {
        Date lastMod = files[0].getTimestamp().getTime();
        FTPFile choice = files[0];

        for (FTPFile file : files)
        {
            if (file.getTimestamp().getTime().after(lastMod))
            {
                choice = file;
                lastMod = file.getTimestamp().getTime();
            }
        }
        return choice;
    }

}

Answer 1

Because the files array is empty. It's written.