Can anyone good Online material for design patterns and object oriented principle?

Answer 1

Thanks Denise

Answer 2

Desgin patterns something like singleton , factory and repository pattern.

You might heard these concepts

Answer 3

Hello vinod kumar

You will find lessons in the learn section: by the community -> design patterns

https://www.sololearn.com/learn/672/?ref=app

I think this thread is also very helpful:
https://www.sololearn.com/Discuss/2188780/?ref=app