headfirst_design_patterns

http://www.javaguides.net/2018/07/factory-pattern-from-head-first-design-patterns.html

http://www.javaguides.net/2018/07/decorator-pattern-from-head-first-design-patterns.html

http://www.javaguides.net/2018/07/template-pattern-from-head-first-design-patterns.html

http://www.javaguides.net/2018/07/observer-pattern-from-head-first-design-patterns.html

http://www.javaguides.net/2018/07/facade-pattern-from-head-first-design-patterns.html