Question

I am struggling to explain oop concepts in java.

A major tenet in oop is that objects have methods; so Object.method(); works.
I am contrasting this with procedural programming in which one must do method(Object).

Is this called encapsulation?

What are the advantages of the oop way?

Answer 1

2 more advantages of OOP are re-use and polymorphism.

ReUse:
If you use doSomething(Object) in one file or one program, it may work fine for that program. Now, imagine that you need to use your Object in another program. You will need to duplicate the doSomething() method in your new program (probably copy and paste it). This may work, but is bad practice and makes maintaining that logic a nightmare. If the doSomething() logic is a function inside Object then that logic “lives” with the object.

Polymorphism:
Imagine another case where Object is just one of many similar types. If you take advantage of Interfaces, many objects can implement the doSomething() function to suit their specific needs.

Example:

interface ICar
{
    void doSomething();
    void getFuel();
}

class GasCar : ICar
{
    public void doSomething()
    {
        //do something a gas car would do
    }
    public void getFuel()
    {
        //logic to pull gas out of a tank
    }
}

class ElectricCar : ICar
{
    public void doSomething()
    {
        //do something an electric car would do
    }
    public void getFuel()
    {
        //logic to pull fuel out of a battery
    }
}