FolderFilesRenamer is a simple changeable Java Class for renaming folder files according to your needs.
Just change the body of the method renameFile to the naming scheme you want, compile the class with a suitable classname and execute it on a folder by passing the folder path as the first argument, for example:
java EightRandomNumbers pathToFolder
The file was tested manually on macOS. I could not find any bugs, but there still may be some.
Feel free to get in contact and share your experience with FolderFilesRenamer. Bug reports are also very appreciated.