Design principles in Head first design mode

Design patterns are specific applications of design principles, so the design principles in the head first design pattern are recorded below:

1 package changes.
2 multi-use combination less inheritance.
3 Programming for interfaces, not for implementation.
4 works for loosely coupled designs between interacting objects.
Class 5 should be open to extensions and closed for modification.
6 rely on abstractions and do not rely on specific classes.
7 only talk with friends.
8 Don't call me, I'll find you.
Class 9 should have only one reason to change.