Using abstraction in Java makes things less complicated. It means hiding things that aren’t needed and only showing the functions that users should be able to use. In other words, data abstraction is the process of stripping Java objects down to their most basic parts so that only the parts that users need to see are shown.
For example, when you send an email, you only need to put in the email address of the recipient, the subject, and the body. From the user’s point of view, the application shows what you need to do the job. Other implementations, like connecting to the server, formatting the email, and encrypting it, happen behind the scenes. Through abstraction, these steps are hidden from the user.
This article talks about what abstraction is and how it works in Java. It also gives an example of how to use abstraction.
What is the point of abstraction?
Before we look at abstraction in Java, let’s talk about how it works with data. There are abstract classes and abstract methods in Java.
- Abstract Classes
Because Java is an object-oriented programming (OOP) language, abstraction is very important. OOP is all about making objects with data and methods. Every object in Java is part of a class, which means that every object in Java is part of a class.
For instance, you could work with a class called “fruit,” where a banana could be an object. In Java, an object’s behavior (its methods), its interfaces (how it talks to other objects), and its properties are what make it what it is (attributes).
In Java, partial or full abstraction is possible with abstract classes. Having implementations with concrete methods is how you get a partial level of abstraction. Interfaces with abstract types that describe how a class should act are used to get full abstraction.
Here are some rules you should remember when working with abstract classes:
They can have methods that are not concrete (methods without a body).
An abstract class must be declared for a class that has an abstract method.
A class that is marked as abstract can’t be used.
There can’t be any static or final methods in the body of a class.
If a class inherits from an abstract class, it must also implement all the abstract methods of the abstract class.
Abstract Method in Brief
Abstract methods are methods that don’t have a body or a way to do things. You use them when you want to add a method to a class but let child classes decide how to implement it.
Using the abstract keyword, you can say that a method is abstract. It looks like a method signature but doesn’t have a body.
Abstraction of Data and Abstraction of Control
In Java, there are two kinds of abstractions: those that deal with data and those that deal with how things work.
Data abstraction lets you make complex data types like HashMap and HashSet without letting your users know how they work. HashMaps and HashSets are only useful if you know how to use them to organize your data.
Control abstraction is the process of putting all similar, often-used statements into a single unit. This abstraction is used to make functions that do a specific job.
Which Is Better: Data Abstraction or Data Encapsulation?
Data encapsulation is a way for Java to put together data/variables and the method that works on them. It means that people outside of a class can’t see the information in that class. In Java, private data is marked in the class definition with the word “private,” and a get or set method is used to access it.
Both “data encapsulation” and “data abstraction” are important OOP concepts. Both hide important parts of the code from other code users to make the code more secure. They both give limited access to their parts without giving away the details behind them.
The main difference between the two is that data encapsulation tries to hide the data, while data abstraction tries to hide how the data is used.
Why Should You Use Data Abstraction?
When it comes to making applications, abstraction has several benefits:
It does a good job of making complicated things easier for users to do.
Abstraction encourages loose coupling, which makes it easier to find bugs because the implementation and the functions are kept separate.
By letting code be used more than once, abstraction helps make code that works well.
By hiding important implementation details, abstraction makes a system more secure.
Java Example of Abstraction
Look at the following example to see how abstraction works. Say you work for a car rental company and need to send an invoice to a customer. You also want the app to figure out how much the client owes in total.
Example of Abstraction: Abstract Class vs. Interface
You can use an abstract class or an interface to separate things in Java.
In Java, an interface is the plan for a class. It is made up of abstract methods and static constants. Interfaces are like abstract classes in that they can’t be created and can handle at least one method that has been declared but not implemented.
An interface can only tell you what methods a class must implement. An abstract class, on the other hand, can have both data and concrete methods. Also, an interface lets you limit the number of abstract methods that can be declared. With an abstract class, you can’t do this.
In this example, an abstract class was used because single inheritance could not meet the needs of abstraction. This example also used class abstraction to hide how the cost is calculated and how the invoice is processed. So, the user only sees the information that is needed to make an invoice.
How to Begin with Java Abstraction
Abstraction in Java is a great way to limit what you share with your users, and you can choose the level of abstraction you want to use in an application. You can get partial abstraction from concrete methods in abstract classes, and you can get full abstraction from interfaces.
Abstract methods are important when you want a child class to figure out how to do something.
Since Java is an OOP language, data abstraction helps it. It not only helps you give your users only the information they need, but it also makes programming applications easier and less complicated.