Why I should use interface instead of directly declaring method inside of the class without interface
34360
Why would I want to use Interfaces?
63715
What is the purpose for using an empty interface that extends another in Java?
131669
Why Would I Ever Need to Use C# Nested Classes
150870
Java - Method name collision in interface implementation
141587
Is there any reason to declare optional parameters in an interface?
80510
Implements vs extends: When to use? What's the difference?
87784
Do class functions/variables have to be declared before being used?
132306
Java - Interface, instantiating an interface?
131096
Defining methods via prototype vs using this in the constructor - really a performance difference?
27078
When do Java generics require  instead of  and is there any downside of switching?
35653
Should methods in a Java interface be declared with or without a public access modifier?
6853
Interface vs Abstract Class (general OO)
27045
Why is method overloading and overriding needed in java?
7323
What is the point of interfaces in PHP?
125648
Use Data From Class Without A New Init
80633
Java - declaring from Interface type instead of Class
99914
Using properties instead of fields in class methods of the same unit is a bad practice?