Hex File Editor is a Java 1.4 graphical (GUI) application to edit a file as a stream of hexadecimal digits, where each 8-bit byte is represented by two 4-bit "nibbles" (the hex digits). No meaning is attached to the digits, and hence to the contents of the file, so this editing is very raw. You can insert, delete, or replace digits or bytes, and you may view an approximate character equivalent of the digits in plain text (7-bit ASCII).
The primary purpose of a hex editor is to patch or correct specific locations within a file without affecting the rest of the file, something that most word processors can't do. A secondary purpose is to view the exact content of files. (Please read the PDF documentation included in the ZIP file. This program has been released under the GNU General Public License.)