Looking good. Are your example in java 8 or you are using java 8 for refractering ??

Just a word missing

Please give some Swift (ios) examples for refactoring.

Design Patterns with a functional approach

Remove limitation of abstract factory Design pattern

better class diagram for chain of responsibility pattern

Replace temp with query question?

Yup - there is a mistake... in the Context class instead of "return strategy.execute(a, b)" should be "return strategy.algorithm(a, b)", because Strategy class doesn't have "execute" method

Where are the interactive lessons?

Button `Catalog` redirects to refactoring object.