Understanding Encapsulation in Java OOPs with Example

Understanding Encapsulation in Java OOPs with Example
Understanding Encapsulation in Java OOPs with Example


Encapsulation (or OOP Encapsulation) in Java or object-oriented computer programming languages refers to the grouping of data and the methods that work on that data into a single entity. One of the fundamental concepts of object-oriented programming is encapsulation (OOP).

It represents the concept of grouping data and methods that operate on that data into a single unit, such as a class in Java. So what is encapsulation in Java? Let us understand encapsulation in Java OOPs with the help of an example for better understanding.

Design Pattern Based on Encapsulation in Java

The encapsulation concept is utilised for several design patterns in Java, one of which is the Factory pattern used to construct objects. For creating an object of those classes whose construction logic may vary and creating a separate implementation of the same interface, the factory pattern is a better option than the current operator.

JDK’s BorderFactory class is a clear illustration of encapsulation in Java since it generates various forms of Border and encapsulates the Border formation logic. In Java, the singleton pattern encapsulates how you generate an instance using a getInstance() function.

Since an object is generated within one class and not from somewhere else in code, you can actually modify how an object is created without affecting other parts of the code.

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Abstraction vs Encapsulation in Java

Let us know how abstraction and encapsulation in Java differ from each other.

The process or method of obtaining knowledge is known as abstraction.The mechanism or means of containing information is known as encapsulation.
Problems are addressed at the concept or interface stage of abstraction.Problems are addressed at the implementation stage during encapsulation.
Abstraction is a technique for concealing unnecessary information.Encapsulation, on the other hand, is a means of hiding data in a particular entity or unit and a method of protecting information from the outside.
Abstract classes and interfaces may be used to enforce abstraction.Encapsulation may be applied with an access modifier, such as private, protected, or public.
Implementation complications are obscured using abstract classes and interfaces of abstraction.The data is hidden during encapsulation by utilising getter and setter methods.
The objects that aid in abstraction are encapsulated.The objects that originate from encapsulation do not need to be abstracted.

Frequently Asked Questions

Why do we use encapsulation in Java?

The reasons why encapsulation is used in Java include the following:

1. Flexibility: It is easier and more versatile to modify the encapsulated code to meet new specifications. For instance, if the condition for adding/removing an employee’s project shifts, we can quickly amend the reasoning in the setter method () or given methods.

2. Reusability: Encapsulated functionality may be reused through different applications or inside the same programme.

3. Maintainability: Since application code is encapsulated in different units (classes, interfaces, procedures, getters/setters, and so on), it is simple to modify or upgrade a portion of the application without disrupting other components, minimising the developer’s effort and time.

4. Testability: Writing unit tests with an encapsulated class is simpler since the member variables are not spread all over the place, saving the tester time and effort.

5. Data Hiding: Since the member variables are not available to the caller function, the caller has little knowledge about the internal logic of the class. The caller just knows the parameters that must be transferred to the setter function (or any method) for it to be initialised with that value.

How do you explain encapsulation?

Encapsulation (or OOP Encapsulation) in object-oriented computer programming languages refers to the grouping of data and the methods that work on that data into a single entity. Many programming languages make extensive use of encapsulation in the form of classes.

A class is a program-code template that makes it possible to create an object with both variables (data) and behaviours (functions or methods). A class is an indicator of encapsulation in computer science since it consists of data and methods packed into a single object.

Encapsulation may also apply to a process that restricts direct access to some aspects of an object, such as preventing users from accessing state values for all variables of a certain structure. Encapsulation may be used to conceal data representatives and data functions or methods connected with a class or object that has been instantiated.

What is abstraction and encapsulation in Java?

Abstraction is an object-oriented programming concept that “shows” only important attributes while “hiding” irrelevant details. The primary goal of abstraction is to shield users from unwanted information.

Abstraction is the process of selecting data from a wider pool to display only specific information of an entity to the consumer. It aids in the reduction of programming complexity and effort. It is one of the most crucial concepts in OOPs.

What are polymorphism and encapsulation?

Polymorphism refers to the ability to exist in many ways. Variables, functions, and objects in Java and Python can have several different types. Polymorphism is classified into two types: run-time polymorphism and compile-time polymorphism. The run-time will take on various forms when the programme runs, and compile-time can take on different forms during compilation.

Polymorphism in Object-oriented programming aims to enforce simplicity, allowing programs more extendable and software easier to manage. Inheritance enables the development of class hierarchies in which a base class passes on its behaviour and attributes to a derivative class. You may then alter or expand its capabilities. Polymorphism means that the correct procedure is implemented depending on the form of the calling object.

Encapsulation is the binding of data with the code that manipulates it. It protects the data and the code from outside intrusion.

A car’s power steering system is an example. A car’s power steering is a dynamic mechanism of several closely connected parts and operates synchronously to transform the car in the desired direction. It also regulates the amount of power supplied by the engine to the steering wheel.

However, only one interface is visible to the outside world, and most of the complexity is concealed. Besides that, the steering assembly is complete and self-contained. It has no impact on the operation of any other process.

What is an encapsulation example?

Below is an example of four fields with setter and getter methods.

//A Account class which is a fully encapsulated class.
//It has a private data member and getter and setter methods.
class Account {
//private data members
private long acc_no;
private String name,email;
private float amount;
//public getter and setter methods
public long getAcc_no() {
return acc_no;
public void setAcc_no(long acc_no) {
this.acc_no = acc_no;
public String getName() {
return name;
public void setName(String name) {
this.name = name;
public String getEmail() {
return email;
public void setEmail(String email) {
this.email = email;
public float getAmount() {
return amount;
public void setAmount(float amount) {
this.amount = amount;

What are the benefits of encapsulation?

The most significant benefit of utilising encapsulation in Java is data security. The following are some of the benefits of encapsulation:

1. Encapsulation protects an object from unauthorised client access.
2. Encapsulation provides entry to a stage, thus hiding the intricate information under the level.
3. It lowers the number of human errors.
4. Its server management is easier.
5. It simplifies the application’s understanding.

Key Takeaways

There are various divisions in a company, such as the accounts section, the finance section, the sales section, and so on; this is what we call encapsulation. When combined with abstraction, encapsulation in Java becomes a useful technique for easily hiding data and reducing code complexity. Learn data structures and Java algorithms the easy way from Coding Ninjas. Try for free now!