This repo contains some examples of Design Patterns in Java; it was split off from my main javasrc repo to keep the latter from becoming bottom-heavy.
The original book that popularized Design Patterns - after they were in use for a decade in the CS community - is Design Patterns: Elements of Reusable Software, by Gamma, Helm, Johnson and Vlissides, known more concisely as the Gang of Four or even the GoF.
A less academic, more memorable read is O’Reilly’s Head-First Design Patterns.
The OO chapter of my Java Cookbook, 3rd edition.
Command Pattern, in Oracle’s Java Magazine May/June 2018. http://www.javamagazine.mozaicreader.com/MayJune2018/Default/15/0#&pageSet=15
State Pattern, in Oracle’s Java Magazine, July/August 2018. http://www.javamagazine.mozaicreader.com/JulyAugust2018#&pageSet=66
Visitor Pattern, in Oracle’s Java Magazine, September/October 2018. http://www.javamagazine.mozaicreader.com/SeptemberOctober2018/Default/66/0
Decorator Pattern, in Oracle’s Java Magazine, November/December 2018.