This repository contains working project code used in video Course by Packt Publication with title "Learn Design Patterns with Java " authored by "Aseem Jain".
https://www.packtpub.com/application-development/learn-design-patterns-java-9-video
https://github.com/premaseem/DesignPatternsJava9
This course exposes you to a very rich github code repository which has around 50 different working code projects. Code is organized in separate branches, which means all code related to singleton design pattern is in single-pattern branch and all code related observer pattern is observer-pattern branch. Each branch has related diagrams in the branch. The commit history also helps you evovle the code. You are supposed to clone or download the code base and exectue it locally or play with it for deeper learning. You can own the repo by forking it and modify code as much as you want. Remember the rule, more you code better you learn ;-)
This repository has several branches and each branch contains code of a design pattern. https://github.com/premaseem/DesignPatternsJava9/tree/pattern-name
To look at code of Decorator pattern you might have to switch to branch decorator pattern link: https://github.com/premaseem/DesignPatternsJava9/tree/decorator-pattern
https://premaseem.wordpress.com/category/computers/design-patterns/
https://www.facebook.com/DesignPatternGuru/
Note: This code base will work on Java 9 and above versions.