OOPs concepts in Java With Examples 

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We will study the fundamentals of Java’s OOPs ideas in this blog. The model of object-oriented programming offers a variety of concepts, including inheritance, abstraction, polymorphism, etc. These ideas seek to incorporate real-world objects into programs and develop operational procedures and variables to reuse them without jeopardizing security. Java, C++, C#, JavaScript, Python, Ruby, Perl, Smalltalk, and other of the most popular and important object-oriented programming languages are just a few examples.

What is the OOPs Concept?

Java programming, which is used to create programs using classes and objects, is fundamentally based on object-oriented programming. Oops, can also be described as data controlling for code access. In this method, programmers specify a data structure’s data type as well as the operations that will be performed on it.

What are OOPs in java? 

The goal of OOps in Java is to increase code readability and reuse by effectively defining Java programs. Abstraction, encapsulation, inheritance, and polymorphism are the four basic foundational concepts of object-oriented programming. These ideas seek to incorporate actual entities into programming.

List of OOPs Concepts in Java

  • Objects
  • Classes
  • Object 
  • Class
  • Abstraction
  • Inheritance 
  • Polymorphism
  • Encapsulation
OOPs concepts in Java

Detailed Course on Java OOPs

What are Objects?  

In Java or any other language, objects that are formed from classes are always referred to as instances of that class. They exhibit states and actions.

These things are always real beings or things that can be discovered in the real world. They are also known as world run-time entities. These are all-inclusive and comprise the methods and attributes that make data usable. Both physical and logical data can be considered objects. It occupies some memory space and contains addresses. A dog, a chair, a tree, etc. are a few examples of objects.

When we perceive animals as objects, they have states like color, breed, and name, as well as behaviors like feeding and waving their tails.

Let’s say we have a class called My book, and we use the term new to indicate the class name, followed by the object name.

Object Example 1:

Public class Mybook {
int x=10;
Public static void main (String args []) {
Mybook Myobj= new Mybook ();
System.out.println(MyObj.x);
}
}

The example above creates a new object and returns the value of x, which may be the number of books.

Mybook Myobj= new Mybook ();

This is the statement used for creating objects.

System.out.println(Myobj.x);

The value of an object x can be returned with this statement.

Multiple objects can be created in the same class, and we can create an object in one class and access it in another. Remember that the class name and the java file name always remain the same when using this strategy for the better class organization.

Example 2:

In the example that follows, we’ll see how to create many objects in the same class and access them from another class.

  • Mybook.java
1
2
3
4
Public class Mybook {
int x=10;
int y=8;
}
  • Count.java
Class Count {
Public static void main (String [] args)
{
Mybook myobj1 = new myobj1();
          Mybook myobj2 = new myobj2();
           System.out.println (myobj1.x);
System.out.println (myobj2.y);
}
}

The results of this program’s compilation are 10, and 8, respectively.

What are Classes?

For constructing objects, classes resemble object constructors. The group of objects is referred to as a class. It is claimed that classes are logical quantities. Classes don’t take up any memory space. A class is also referred to as an object’s template. Members of classes can be fields, methods, or constructors. Both static and instance initializers are present in a class.

An example of a class declaration is:

1. Modifiers:

These can be public or default access.

2. Class Name:

Initial letter

3. Superclass:

A class can only extend (subclass) one parent.

4. Interfaces:

A class can implement more than one interface.

5. Body:

Body surrounded by braces, { }.

To construct a class, use the class keyword. The following is a brief generalization of the class definition:

class classname {
type instance variable 1;
type instance variable 2;
.
.
.
type instance variable n;
type methodname 1 (parameter list) {
// body od method 
}
type methodname 2 (parameter list) {
// body od method 
}
type methodnamen (parameter list) {
// body od method 
}
 }

Instance variables are the variables or data declared inside a class. The methods are always composed of code. As a result, a class’s defined variables and methods are referred to as its members. All of the methods have the same format as the main (); neither static nor the public is specified for these methods.

What is Abstraction?  

Abstraction is a procedure that only shows the information that is necessary and conceals the irrelevant information. We might say that data concealing is abstraction’s primary goal. Abstraction reduces programming labor and complexity by choosing data from a wide pool of data to display the information required.

Additionally, abstract methods and classes exist. A class that declares one or more abstract methods is known as an abstract class. A method that has a method specification but no implementation is said to be abstract. The same pieces of data can also be used in multiple applications—abstract classes, generic sorts of behaviors, and object-oriented programming hierarchy—once we have modeled our object using data abstraction. When two or more subclasses do the same operation differently and use various implementations, abstract methods are utilized. Both normal methods and abstract methods can be found in an abstract class.

Let’s examine an abstraction example now.

Let’s say we want to make a student application and ask for the student’s personal data.

We gather the information listed below.

  • Name 
  • Class
  • Address
  • Dob
  • Fathers name
  • Mothers’ names and so on.

Not all of the data we have gathered may be necessary in order to complete the application. So, we decide which information is necessary to complete the application. As a result, we have retrieved, eliminated, and chosen the data, namely the student information, from vast data. In the oops notion, this activity is referred to as abstraction.

Abstract class example:

//abstract parent class 
        Abstract class animal {
         //abstract method 
      public abstract void sound ( ) ;
         }
     Public class lion extends animal {
      Public void sound ( ) {
System.out.println (“ roar “ );
}
public Static void main ( String args [ ] ) {
 animal obj = new lion ( );
obj. sound ();
}
}

Output:

Roar

What is Inheritance?

One way for an item to obtain or inherit another object’s properties is through inheritance, which also permits hierarchical classification. The concept behind this is that we may build new classes on top of older classes; in other words, when you inherit from an older class, you can use its fields and methods again. The parent-child relationship is represented by inheritance.

For instance, a whale falls within the category of marine animals, which itself falls under the category of mammals. We employ top-down classification, often known as hierarchical classification. Mammals are a more specialized type of creature, and as such, they have more specialized characteristics, such as teeth, cold-blooded or warm-blooded, etc. This belongs to the animal subclass, whereas animals belong to the animal subclass. A class that inherits superclass properties is said to be a subclass. This is referred to as a derived class. A base class or parental class from which a subclass receives its properties is known as a superclass.

The primary purposes of inheritance are method overriding and R:

The extended keyword is used to inherit a class.

There are five different inheritance structures: hierarchical, single, multilevel, and multiple.

  • Single level

  The derived class in this one class, or class, inherits attributes from the parent class. This makes it possible to reuse the code and gives it new functionalities. For instance, class b inherits traits from class a.

Class B is a derived class, while Class A is the base or parental class.

Syntax: 

Class a {
…
}
Class b extends class a {
…
}
  • Multilevel

This particular class is descended from another class that is descended from yet another class, i.e., this class has multiple parental classes, which is why the multilevel inheritance is referred to as such.

Syntax:

Class a {
….
}
Class b extends class a {
….
}
Class c extends class b {
… 
}
  • Hierarchical level 

In Java, multiple inheritances are not supported because they create ambiguity; instead, this type of inheritance may only be accomplished using interfaces. This is the mix of multiple and multilayer inheritances.

Think about how to class a serves as the parent or base class for classes b and c, which in turn serves as the parent or base classes for class d. Classes b and c are descended from class a, and classes d are descended from classes b and c.

The extend keyword is used in the following program to construct a subclass add and a superclass adds, both of which are named sub.

// a simple example of inheritance 
//create a superclass
Class Add {
int my;
int by;
void setmyby (int xy, int hy) {
my=xy;
by=hy;
}
}
/create a sub class
class b extends add {
int total;
void sum () {
public Static void main (String args [ ] ) {
b subOb= new b ( );
subOb. Setmyby (10, 12);
subOb. Sum ( ) ;
System.out.println(“total =” + subOb. Total);
}
}

It gives output as – total = 22

What is Polymorphism?

Polymorphism is a term that describes a variety of shapes or a process that carries out the same operation in several ways. It happens when there are numerous classes connected through inheritance. There are two types of polymorphism: compile-time polymorphism and run-time polymorphism. When we overload a static method in Java, this is an example of compile-time polymorphism. A technique in which a call to an overridden method is resolved at run time rather than compile time is known as run time polymorphism, also known as dynamic method dispatch. In this method, the reference variable is always used to call the overridden method. We can implement polymorphism by using method overloading and method overriding. The term “polymorphism” is generally used to describe one interface,

Example:

public class Bird {
…
Public void sound ( ) {
System.out.println ( “ birds sounds “ );
}
}
public class pigeon extends Bird {
…
@override
public void sound ( ) {
System.out.println( “ cooing ” ) ;
}
}
public class sparrow extends Bird ( ) {
….
@override
Public void sound ( ){
System.out.println( “ chip ” ) ;
}
}

In the aforementioned illustration, we can hear a typical action sound (), although there are other ways to carry out the same action. One example of polymorphism is this.

Java polymorphism can be divided into two categories:

  1. Static / Compile-Time Polymorphism
  2. Dynamic / Runtime Polymorphism

What is Compile-Time Polymorphism in Java?

Static polymorphism also referred to as compile-time polymorphism in Java, is implemented at compile time by method overloading.

What is Runtime Polymorphism in Java?

Java’s Dynamic Binding also referred to as runtime polymorphism, is used to call an overridden method that is dynamically resolved at runtime rather than at compile time.

What is Encapsulation?

One of the OOPs principles is encapsulation, which is the process of combining data and code into a single entity while protecting both from outside intervention and misuse. The data is kept secret from other classes during this procedure and is only accessible through the methods of the current class. Thus, it is sometimes referred to as data concealing. Encapsulation serves as a barrier that keeps others from accessing the code and data. These are managed via a well-laid-out interface.

By designating the variables as private and making the setter and getter methods public, encapsulation can be accomplished. The fields of a class are turned read-only or write-only during encapsulation. Reusability is also enhanced by this technique. For unit testing, encapsulated code is very simple to test.

Example:

class animal {
// private field 
private int age;
//getter method 
Public int getage ( ) {
return age;
}
//setter method 
public void setAge ( int age ) {
this. Age = age;
}
}
class Main {
public static void main (String args []);
//create an object of person 
Animal a1= new Animal ();
//change age using setter 
A1. setAge (12);
// access age using getter 
System.out.println(“ animal age is ” + a1. getage ( ) );
}
}

Output:

Animal age is 12

In this example, we designated an age secret field that is only accessible within the class.

We accessed age using open ways. Getter and setter methods are the names of these techniques. We can limit illegal access from outside the class by making age secret. Thus, this is referred to as data concealing.

Coupling in Java

The relationship between two classes is referred to as coupling. It denotes the understanding of one object or class by another. The dependent changes in the other class will be impacted if one class changes its characteristics or behavior. As a result, the degree of interdependence between the two classes will determine these changes. Tight coupling and loose coupling are the two different types of coupling.

Tight Coupling:

A class is considered to have a tight coupling with another class if there is a strong relationship between them.

public class College{
public void status() {
System.out.println("College is open today");
}
}
public class Student{
College obj = new College();
public void goToCollege() {
obj.status();
}
}

The student class in the aforementioned code example is dependent on the college class. In other words, any change in a college class necessitates a change in the student classes. As a result, the student class and the college class are closely related in this situation.

Loose Coupling:

A class is considered to have a loose coupling with another class if there is just a weak relationship between them. Tight coupling is preferable to lose coupling. As seen below, interfaces can assist a class to accomplish this.

public interface College{
void status();
}
class CollegeStatus1 implements College{
public void status() {
System.out.println("College is open monday to friday");
}
}
class CollegeStatus2 implements College{
public void status() {
System.out.println("College is open on saturday");
}
}
public class Student{
College obj = new CollegeStatus1();
public void goToCollege() {
obj.status();
}
}

CollegeStatus1 and CollegeStatus2 are loosely connected in the aforementioned code example. In this instance, the CollegeStatus1 or CollegeStatus2 classes are not closely or directly related to the student class. A dependency injection approach is used to establish loose coupling, allowing students to enroll in college with any class that has created a college interface. Additionally, it implies that whenever the college is open on Saturday, we can use CollegeStatus2.

Cohesion in Java

Java Cohesion gauges how closely tied and purposefully focused a class’s methods and attributes are on carrying out a specific, well-defined mission for the system. This is used to describe how tightly focused a class’s single responsibility is. For code reuse, it is best to preserve the more cohesive classes. Low cohesive classes are challenging to maintain since their methods and properties don’t relate logically to one another. It is always preferable to have classes that operate well together to retain students’ attention on a single task.

Low Cohesion

We have a class called Book in the code below. However, it lacks cohesion because the class’s characteristics and methods are less concentrated and independent. There should be material in this class that relates to the Book. As a result, the way of using the person’s name and age is helping to make this classless.

class Book{
int price = 299; //related attribute
String name = "Sam"; //unrelated attribute
//related methods to Book class
public String author(String name) {
return name;
}
public String title(String subject) {
return subject;
}
public int id(int number) {
return number;
}
//unrelated methods to Book class
public int age(int age) {
return age;
}
}

High Cohesion:

The class is deemed to be very cohesive when it has a single, clearly defined goal or assignment. As a result, if we delete the information pertaining to the individual from the example code above, the class becomes extremely cohesive, as demonstrated below.

class Book{
int price = 299; //related attribute
//related methods to Book class
public String author(String name) {
return name;
}
public String title(String subject) {
return subject;
}
public int id(int number) {
return number;
}
}

Association in Java

A relationship between two distinct classes that is established with the aid of their objects is called an association. The relationship between two or more objects is described. One-to-one, one-to-many, many-to-one, and many-to-many associations are all possible. Consider the relationship between the bus and the passengers to help us better understand this with examples from real-world situations. A bus can have only one driver(one-to-one). Many passengers can associate with the single bus(many-to-one). A single passenger can associate with many different buses(one-to-many). Also, many passengers can associate with the many different buses(many-to-many). One object is associated with another object to use the functionality and services provided by another object.

Consider the following code below:

//class bus
class Bus
{
private String name;
// bus name
Bus(String name)
{
this.name = name;
}
public String getBusName()
{
return this.name;
}
}

//passenger class
class Passenger
{   
// passenger name
private String name;
// passenger seat id number
private int seatId;
Passenger(String name, int seatId)
{
this.name = name;
this.seatId = seatId;
}
public String getPassengerName()
{
return this.name;
}
public int getPassengerId()
{
return this.seatId;
}
}

//Association between both the
//classes in the main method
class Demo
{
public static void main (String[] args)
{
Bus bus = new Bus("Shree Travels");
        Passenger psg = new Passenger("Sneha", 52);
System.out.println(psg.getPassengerName() + " with seat number " + psg.getPassengerId()
+ " is a passenger of " + bus.getBusName());
}
}

Output:

Sneha with seat number 52 is a passenger of Shree Travels

Explanation:

The two distinct classes Bus and Passenger in the example above are connected via their Objects inside the class Demo. By utilising the idea of association, we can establish the connection between two separate classes in this manner. There can be a lot of passengers on a bus, therefore there is a one-to-many relationship.

There are two different types of association:

  1. Aggregation
  2. Composition

Let’s discuss the two in detail.

Aggregation

Java A relationship between an object including other things is represented by the weak association known as aggregation. This illustrates the link between a component and a whole, where a part can exist without a whole. Let’s look at a relationship between a group and an individual as an example. A Person may be a member of several Groups. So, a Group can contain a number of Persons. However, the Person object will not be destroyed if we delete a Group. The aggregate displays the Has- a connection, often known as a one-way or unidirectional association. For instance, the group can have people, but it is impossible and unidirectional for people to have the group. Both entries in this area have a chance of surviving on their own, therefore eliminating one won’t have an impact on the other. As a result, both objects can be aggregated independently.

Considering the following code example:

import java.util.*;

//person class
class Person
{
private String name;
private int age ;
Person(String name, int age)
{
this.name = name;
this.age = age;
}
public String getName() {
return name;
}
public int getAge() {
return age;
}
}

/* Group class contains the list of person
Objects. It is associated with the person
class through its Object(s). */

//group class
class Group
{
private String groupName;
private List<Person> persons;
Group(String groupName, List<Person> persons)
{
this.groupName = groupName;
this.persons = persons;
}
}

//main method
class Demo
{
public static void main (String[] args)
{   
//creating objects of person class
Person a = new Person("Tanmay", 17);
Person b = new Person("Sam", 18);
Person c = new Person("Pitu", 19);
Person d = new Person("Khushi", 20);
//making a list of persons belongs to social welfare group
List<Person> p1 = new ArrayList<>();
p1.add(a);
p1.add(c);
//making a list of persons belongs to drama fest group
List<Person> p2 = new ArrayList<>();
p2.add(b);
p2.add(d);
//creating objects of group class
Group swGrp = new Group("Social Welfare", p1);
Group dfGrp = new Group("Drama Fest", p2);
//before deleting drama fest group
System.out.println("List of persons in Drama Fest group:");
for(Person p : p2) {
System.out.println("Person name: " + p.getName() + ", Age:" + p.getAge() + ", Group: Drama Fest");
}
//deleting drama fest group
dfGrp = null;
//after deleting drama fest group
//person list will not destroy
System.out.println("List of persons after deleting Drama Fest group:");
for(Person p : p2) {
System.out.println("Person name: " + p.getName() + ", Age: " + p.getAge());
}
}
}

Output:

List of participants in Drama Fest:

Sam, age 18, and the Drama Fest group

Khushi is a 20-year-old member of the Drama Fest group.

individuals listed after deleting the Drama Fest group:

Sam, an 18-year-old man

Khushi, a 20-year-old individual

Explanation:

We can see that the two classes, Person and Group, are connected to one another in this instance using objects. There are two organisations: drama fest and social welfare. We used the person class to construct these groupings. There is a list of people in the group. According to the output, Sam and Khushi are two of the individuals in our Drama Fest group. By changing the instance of group equals to null after that, we eliminated this group. Despite the group being deleted, our list of people is still intact because of the weak association, or aggregation.

Composition in Java

Java A part of a total connection that cannot exist without the entire is represented by the association known as composition. Let’s look at a relationship between a school and a room as an example. The school building is made up of a number of rooms. Without an existing school object, there is no probability of an existing dependant object since if the school object automatically dissolves, all the room objects also automatically destroy. As a result, these have a close link that is known as composition. If a whole is removed, all of its components are also removed. Therefore, composition is an element of relationship.

When two entities are composed, the resultant entity is dependent on the other object to exist. As a result, both entities are dependent on one another in their makeup.

Consider the following code example:

import java.util.*;   
// activity room class
class ActivityRoom {  
    public String subject;   
    public int id;   
    
    ActivityRoom(String subject, int id)   
    {   
        this.subject = subject;   
        this.id = id;   
    }   
    
}   
// department class   
class Department {   
private String name;
    //list of activity rooms in a department.   
    private List<ActivityRoom> ar; 
    
    Department(List<ActivityRoom> ar)  
    {  
        this.ar = ar;  
    }   
    // Getting total number of colleges  
    public List<ActivityRoom> getActivityRoomsInDepartment()   
    {   
        return ar;   
    }   
}   
class Demo {   
    public static void main(String[] args)   
    {   
        // Creating the Objects of activity room class.   
     ActivityRoom a1 = new ActivityRoom("Technical", 601);   
     ActivityRoom a2 = new ActivityRoom("Business", 602);   
     ActivityRoom a3 = new ActivityRoom("Economics", 603);  
     
        // making the list of activity rooms.   
        List<ActivityRoom> act = new ArrayList<ActivityRoom>();   
        act.add(a1);   
        act.add(a2);   
        act.add(a3);  
        
        // Creating the Object of department class. 
        Department d = new Department(act); 
        
        // making the list of activity rooms in department.   
        List<ActivityRoom> arlist = d.getActivityRoomsInDepartment();   
        for (ActivityRoom a : arlist) {   
            System.out.println(a.subject + " activity room with id " + a.id);   
        }  
        
    }   
}

Output:

With ID 601, the technical activity room

Room for business activity with ID 602

With ID 603, the economics activity room

Explanation:

We have two classes here. Room for activities and Department. a division made up of many subject-specific activity rooms. The activity room cannot exist without the department, hence if the department is eliminated, all activity rooms contained within it will also be destroyed. Because of this, it is composed.

Methods in Java

A Java method is a section of code or group of statements used to carry out a certain task or operation. This can be applied multiple times in order to achieve code reuse. Additionally, it makes the code easily modifiable and readable. Only when a method is called or invoked does it actually run. In Java, there are two types of methods: pre-defined and user-defined. The methods that are already specified in the Java class libraries are known as predefined methods. A method is referred to as being user-defined when it is created by the user or programmer. User-defined methods can be changed to suit the situation.

Let’s talk about:

  • Static method in Java
  • The abstract method in Java
  • Finalize method in Java
  • Equals method in Java

Static Method in Java

Static methods are those whose declarations contain the static keyword. In other terms, a static method is a method that belongs to a class rather than an instance of a class. By placing the term “static” before the method name, we can also construct a static method. A static method’s key advantage is that it can be called without first generating an object. It is used to define instance methods and has access to and control over members of static data. A typical illustration of a static method is the main() method.

Example:

public class Demo  
{  
public static void main(String[] args)   
{  
displaymethod();  
}  
static void displaymethod()   
{  
System.out.println("It is an example of static method.");  
}  
}

Output:

It is an example of a static method.

Abstract Method in Java

An abstract method is one that uses the keyword abstract in its declaration. There is no implementation, body of code, or block of code for the abstract method. If a class has an abstract method, it should be marked abstract. The abstract method must always be stated in an abstract class. A class should be declared abstract if it has an abstract method, but the reverse is not true, therefore an abstract class need not require an abstract method to be present. Additionally, if a regular class extends an abstract class, the extending class must either implement all the abstract methods of the abstract parent class or be explicitly designated abstract.

Example:

//abstract class area
abstract class Area{
 /* These two are abstract methods, the child class
  * must implement these methods
  */
 public abstract int areaSquare(int s);
 public abstract int areaRectangle(int l, int b);
 //Normal method 
 public void display(){
System.out.println("Normal method in abstract class Area");
 }
}
//Normal class extends the abstract class
class Demo extends Area{

 /* If we don't provide the implementation of these two methods, the
  * program will throw compilation error.
  */
 public int areaSquare(int s){
return s*s;
 }
 public int areaRectangle(int l, int b){
return l*b;
 }
 public static void main(String args[]){
Area a = new Demo();
System.out.println("Area of square " + a.areaSquare(9));
System.out.println("Area of rectangle " + a.areaRectangle(3,4));
a.display();
 }
}

Output:

Size of the square 81

the rectangle’s 12 area

Area’s standard method in the abstract class

Final Method in Java

A final method is one that has been deemed to be the last one. A final method is inviolable. As a result, the child class can still call the parent class’ final method without any issues, but it is not permitted to override it. This is so that the method cannot be modified by the subclass, which is the fundamental goal of declaring a method final.

Example:

class DemoParent{  
final void method(){
System.out.println("Parent class final method");
}  
}  
     
class Demo extends DemoParent{  
//error
void method(){
System.out.println("final method modified inside child class");
}  
     
public static void main(String args[]){  
Demo d = new Demo();  
d.method();  
}  
}

Because we are attempting to change the final method inside the parent class’s child class (demo), the code above will produce an error.

Instead of modifying the method, we can use it as shown below:

class DemoParent{  
final void method(){
System.out.println("Parent class final method");
}  
}  
     
class Demo extends DemoParent{
public static void main(String args[]){  
Demo d = new Demo();  
d.method();  
}  
}

Output:

Parent class final method

Equals Method in Java

The Java method.equals() is used to determine whether two objects are equal. Java’s.equals() function is used to determine whether the values of two strings match. Each character is examined separately. The.equals() method should not be confused with the == operator. While the == operator is used for address comparison, the String equals() method compares the two given strings based on the content of the strings. .equals() returns true if all of the contents of both strings match; otherwise, it returns false. It returns false if none of the characters match.

Let’s use an illustration to better grasp this:

public class Demo {
    public static void main(String[] args)
    {
        String s1 = "GreatLearning";
        String s2 = "GreatLearning";
        String s3 = new String("GreatLearning");
        System.out.println(s1 == s2); // true
        System.out.println(s1 == s3); // false
        System.out.println(s1.equals(s2)); // true
        System.out.println(s1.equals(s3)); // true
    }
}

S1 and S3 are pointing to two separate objects in memory, despite the fact that they were both created with the same field (content). hence at various addresses. As a result, the == operator returns false and the.equals() method returns true because both have greatLearning similar material.

Message Passing in Java

In terms of computers, message passing is a phenomena that occurs when processes communicate with one another. In object-oriented programming, it is a method of communication. In Java, passing a message from one thread to another thread is the same as sending an object. It is used when shared memory is not available and when communicating across threads is not possible using shared variables like monitors. When a programme uses message passing, it sends a message to a process, which it then uses to execute its own functionality or code. Message passing is simple to use, performs well, and allows us to create extremely large parallel models.

It comes in both synchronous and asynchronous forms.

  • When the objects are active at the same moment, synchronous message passing takes place.
  • The receiving object may be unavailable or otherwise occupied when the asking object sends an asynchronous communication.

Can Polymorphism, Encapsulation and Inheritance work together?

The programming environment we create when we combine inheritance, polymorphism, and encapsulation facilitates the creation of programmes that are much more durable and scalable than those that follow the program-oriented model. The foundation for reusing the code that we have invested time, effort, and testing in is a well-designed conceptual model of the hierarchy of classes. We can migrate our implementations over time without affecting code that depends on the open interfaces of our classes thanks to encapsulation. We can write understandable, legible, and tidy code thanks to polymorphism.

As we all know, the processes of encapsulation, polymorphism, and inheritance are used to combine separate pieces to create an object, such as a car, phone, etc. In the case of computer programmes, this is accurate. The many components of complicated programmes are combined using object-oriented principles to create a solid, dependable, and manageable whole.

Java’s built-in class libraries, which heavily rely on encapsulation, polymorphism, and inheritance, contain many of the capabilities that the language offers.

Let’s look at a real-world illustration. From one perspective, humans are a sort of heredity, whereas cars are more like to the programmes we write. All drivers rely on their ancestry to operate various kinds of automobiles. Due to the wide variety of vehicles available to us, some of which have unique features, people interact with the features of all sorts of automobiles. Engine, brake, and other device implementation falls under encapsulation before reaching polymorphism. We have a variety of alternatives for the anti-lock braking system, conventional braking system, and power braking system on the same car. Polymorphism refers to a single vehicle with many braking system configurations. This illustration demonstrates how polymorphism, inheritance, and encapsulation are combined.

Advantages of OOPs Concept 

Some of the advantages are:

  • Re-usability

Reusability refers to the idea of “write once, use it several times,” or reusing some facilities rather than continually developing them. This can be accomplished by using classes. It can be utilised numerous times as needed.

  • Data redundancy 

It is one of oops’ most significant advantages. When the identical piece of data is stored in two locations, this circumstance arises at the data storage. We may simply build generic class definitions for similar functionalities by inheriting them if we wish to apply similar functionality across numerous classes.

  • Code maintenance

Since new objects can be produced with just minor variations from the current ones, it is simple to adapt or maintain existing code. Users can avoid performing repetitive labour and updating old codes by adding new changes thanks to this.

  • Security

Data hiding and abstraction are used to filter out restricted exposure, ensuring that only the data that is absolutely necessary for viewing is made available while maintaining security.

  • Design benefits

Better designs are produced as a result of the designers’ longer and more thorough design phases. It will be simpler to programme each non-oop independently once the programme has hit its critical constraints.

  • Easy troubleshooting

Encapsulation object usage is self-restrictive. Therefore, any issues that developers run into can be quickly resolved. Additionally, there won’t be any chance for coding fraud.

  • Flexibility 
  • Problem-solving

Disadvantages of OOPs Concept 

  • Effort – These programs are the result of a lot of work.
  • Speed: When compared to other programmes, these programmes run more slowly.
  • Size – OOPs programmes are larger than other types of programmes in terms of size.

Differences between Object-Oriented Programming, Procedural Oriented Programming?

OOPs concepts in Java

Difference between an object-oriented programming language and an object-based programming language?

OOps in Java FAQ

What are the OOPS concepts in Java?

Object-oriented programming is known as OOPs. Java’s OOPs structure programs around a variety of objects and clearly defined interfaces. Abstraction, encapsulation, inheritance, and polymorphism are the OOPs concepts used in Java. These ideas seek to incorporate actual entities into programming.

What are the 4 basics of OOP?

Abstraction, encapsulation, inheritance, and polymorphism are the four cornerstones of OOP. The main principles of Java’s Object-Oriented Programming are these.

What are the OOPS concepts in Java with examples?

OOPs, or object-oriented programming system, are Java programming ideas. The OOPs ideas in Java are listed here along with examples:

1. Class
2. Object
3. Inheritance
4. Polymorphism
5. Abstraction
6. Encapsulation
7. association
8. Aggression
9. Composition

What explains the concept of Oops?

OOPs assist in developing a useful technique and reusable variable without sacrificing security. OOPs ideas, which are mostly employed in Java, C#, C++, Python, Perl, Ruby, and other object-oriented programming languages, place an emphasis on data rather than functions.

What are the main features of OOPs?

Classes, Objects, Encapsulation, Data Abstraction, Polymorphism, and Inheritance are the primary components of OOPs concepts in Java.

Why are OOPs concepts used?

To include numerous real-world principles in programming, such as polymorphism, abstraction, inheritance, etc., Java uses OOPs concepts. Connecting the data and functions can also be used to guarantee the safety of the code.

What are the advantages of OOPs?

The use of OOPs concepts in Java has many advantages. Below are a few of the main benefits: Benefits of design include reusability, code upkeep, data redundancy, security, simple troubleshooting, problem-solving, and flexibility. One of the fundamental commonly used development methodologies is Java OOPs.

What is polymorphism in OOPs?

Polymorphism in OOPs is the method that enables us to carry out a single action in a variety of ways. When different classes are related to one another by inheritance, this happens. The two types of polymorphism are as follows. Specifically, runtime polymorphism and compile-time polymorphism. It aids in simplifying things for us.

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