Java Programming II 2020

Single-responsibility principle
A class should only have a single responsibility, that is, only changes to one part of the software’s specification should be able to affect the specification of the class.

Open–closed principle
“Software entities … should be open for extension, but closed for modification.”

Liskov substitution principle
“Objects in a program should be replaceable with instances of their subtypes without altering the correctness of that program.” See also design by contract.

Interface segregation principle
“Many client-specific interfaces are better than one general-purpose interface.”

Dependency inversion principle
One should “depend upon abstractions, [not] concretions.”

https://en.wikipedia.org/wiki/SOLID
https://medium.com/@mari_azevedo/s-o-l-i-d-principles-what-are-they-and-why-projects-should-use-them-50b85e4aa8b6

Object − objects have states and behaviors.
Class – defines the grouping of data and code, the “type” of an object
Instance – a specific allocation of a class
Message – sent to objects to make them act
Method – a “function” that an object knows how to perform
Local Variables − variables defined inside methods, constructors or blocks
Instance Variables – variables within a class but outside any method (a specific piece of data belonging to an object)
Class Variables − variables declared within a class, outside any method, with the static keyword
Abstraction – show only “relevant” data and “hide” unnecessary details of object from the user
Encapsulation – keep implementation private and seperate from interface
Polymorphism – process objects differently based on their data type, using same interface
Inheritance – hierarchical organization, share code, customize or extend behaviors

Tutorialspoint Design Patterns in Java Tutorial
https://www.tutorialspoint.com/design_pattern/index.htm

Javatpoint Design Patterns in Java Tutorial
https://www.javatpoint.com/design-patterns-in-java

DZone Design Patterns for Begineers with Java Examples
https://dzone.com/articles/design-patterns-for-beginners-with-java-examples

HowToDoInJava Design Patterns Tutorials
https://howtodoinjava.com/design-patterns/

W3spoint Java Design Patterns
https://www.w3spoint.com/java-design-patterns-tutorial-with-examples

SourceMaking Design Patterns
https://sourcemaking.com/design_patterns