Hexditor

Hexditor is a Java-based application you can use to open files of any types in order to view and edit their structure via hexadecimal display. It gives you the possibility to save the code as image files, featuring support for several customization options.

No setup required, besides Java

The entire program's packed in a single executable .jar file that can be saved to a custom directory on the disk or copied to a removable storage unit, in order to directly run it on any PC with Java installed.
It doesn't add new entries to the system registry or create files on the disk without letting you know about it. In order to uninstall it, you just have to delete this item.

Simple GUI for hex editing

When it comes to the interface, Hexditor adopts a large window with a plain appearance and neatly structured layout, where you can resort to the built-in file browser to locate and open a file.
It's possible to modify blocks of code, highlight text selections, as well as change the sign: byte (signed or unsigned), short (16) signed or unsigned, float (32), UTF-8, UTF-16 and others.
The utility enables you to jump to a specific offset, undo and redo actions, cut, copy and paste data, insert information before the cursor's current position (fill with 0x00, 0xFF, 0x20, or delete), toggle the position mark or caret, increase or decrease the font size, as well as make the background black or white. Keyboard shortcuts are supported.

Evaluation and conclusion

It didn't put a strain on the computer's performance in our tests, thanks to the fact that it needed a low amount of CPU and RAM to work properly. No error dialogs popped up and it didn't hang or crash.
To sum it up, Hexditor facilitates a simple interface and advanced settings to help you view and edit the hexadecimal code of files. It's mainly geared toward experienced users.