Encapsulation: The practice of keeping fields within a class private, then providing access to those fields via public methods.
EX: private double price public double getPrice(){ return price }
Inheritance: When one object acquires all the properties and behaviors of a parent object, it is known as inheritance. It provides code reusability. It is used to achieve runtime polymorphism.
EX: We cna have a class called animal and the classes dog and cat extends animal and they have all the methods in the animal class.
Abstraction: Hiding internal details and showing functionality is known as abstraction.
EX: THe animal class becomes abstract and we have a makeSound method and each class overrides that method and is forces to implement that method because every animal makes a sound
Polymosphism: If one task is performed in different ways, it is known as polymorphism. For example: to convince the customer differently, to draw something, for example, shape, triangle, rectangle, etc. In Java, we use method overloading and method overriding to achieve polymorphism.
Ex: the make sound method the dog class goes bark bark but the cat class goes meow meow
Arrays: int[] numbers = new int[3] this array can only hold three elements and is unchangeab.
we can use list to be able to change the values in the array:
List<Integer> numList = new ArrayList<>();
we can change the size how ever we like we also have methods like add, remove ect