CJT at its most fundamental level consists of a Code Block. This Code Block combines a Code Editor, an Assignment panel, and a bunch of other useful tools.
The behind-the-scenes functionality of a Code Block are Revisions and something we call Code Files. Each and every Code Block contains a Master Code File that will hold your Active Code. Every time you hit the Save button, CJT will automatically save a new revision for you. This allows you to go to any of your earlier revisions, load one into the editor, and decide whether to select it as the Active Code revision for the Code Block.
A very powerful feature that only CJT PLUS offers, is for you to create your own User Code Files. This allows you to create mini projects within a Code Block so you can keep your code a lot more organised and maintained. Click Code Files and Revisions for a better explanation.