Review comments on your DG

[okkhoy]

1. Image issues a. don't use yellow color, not visible on low contrast screens b. we don't allow database; from what I understand, your DB is a json file - you can mention it as Json data instead of database c. database doesn't have a description in the component description that follows
2. consider using neutral colors (or no colors), in all the diagrams
3. notation
4. simplify image a. consider splitting the diagram to 3 images as suggested b. make text in each diagram bigger so that it is clearly visible
5. notation
6. notation
7. incorrect; call to sout is not a self invocation
8. throw: though there is no standard notation, it may be better to show the throw as a call to exception object or a control return rather than self invocation

[okkhoy]

9. missing else
10. no need to input code here; can specify condition in plain english
11. better to be stating just the condition; e.g., EMAIL_KEY, NUMBER_KEY and Invalid; the check for variable is assumed to be done.
12. This can be extracted as a SD on its own, and the reference given in add courses.
13. "Sequence Diagram on PlantUML"??
14. missing diagram