Each person object would contain different data attributes since each person is unique. By defining sets of classes that represent and encapsulate objects in a program, the classes can be organized into modules, improving the structure and organization of software programs. Thus, developers often use OOP as a tool when they need to create complex programs since they are easier to reason in terms of classes and their relationships.
Object-oriented programming has four basic concepts: encapsulation, abstraction, inheritance, and polymorphism. Even if these concepts seem incredibly complex, understanding the general framework of how they work will help you understand the basics of an OOP computer program.
Below, we outline these four basic principles and what they entail:. Just like a pill "encapsulates" or contains the medication inside of its coating, the principle of encapsulation works in a similar way in OOP: by forming a protective barrier around the information contained within a class from the rest of the code.
In OOP, we encapsulate by binding the data and functions which operate on that data into a single unit, the class. By doing so, we can hide private details of a class from the outside world and only expose functionality that is important for interfacing with it.
When a class does not allow calling code access to its private data directly, we say that it is well encapsulated. Example: Elaborating on the person class example from earlier, we might have private data in the class, such as "socialSecurityNumber," that should not be exposed to other objects in the program. If a method is written in the person class to perform, say, a bank transaction called "bankTransaction ," that function could then access the "socialSecurityNumber" variable as necessary.
Carefully used, abstraction helps isolate the impact of changes made to the code, so that if something goes wrong, the change will only affect the implementation details of a class and not the outside code.
Example: Think of a stereo system as an object with a complex logic board on the inside. It has buttons on the outside to allow for interaction with the object. When you press any of the buttons, you're not thinking about what happens on the inside because you can't see it. Even though you can't see the logic board completing these functions as a result of pressing a button, it's still performing them. It is invoked by using the class name. The main method is a common example of the static method.
A method that is declared with keyword abstract is called an abstract method. The abstract method does not have an implementation or body, or block of code. The abstract method must always be declared in an abstract class, or we can say that if a class has an abstract method, it should be declared abstract.
A method that is declared final is called a final method. We cannot override a final method. This means the child class can still call the final method of parent class without any problem, but it cannot override it. This is because the main purpose of making a method final is to stop the modification of the method by the sub-class. The above code will throw an error as we are trying to modify the final method inside the child class demo of the parent class demoParent.
As the name suggests in java,. It checks them character by character. One should not confuse. If all the contents of both the strings are the same, then. If all characters are not matched, then it returns false. Even though s1 and s3 are created with the same field content , they are pointing to two different objects in memory. Hence at different addresses. Message Passing in terms of computers is a communication phenomenon between the processes.
It is a kind of communication used in object-oriented programming. Message passing in Java is the same as sending an object, i. It is utilized when threads do not have shared memory and are not able to share monitors or any other shared variables to communicate. In message passing calling program sends a message to a process and relies on that process to run its own functionality or code.
Message passing is easy to implement, has faster performance, and we can build massive parallel models by using it. When we combine inheritance, polymorphism and encapsulation to produce a programming environment, this environment supports the development of far more robust and scalable programs that do the program-oriented model.
A well designed or model of the hierarchy of classes are the basis for reusing the code in which we have spent our time and effort developing and testing. Polymorphism allows us to create a readable, clean, sensible code. As we know, it is through the applications of encapsulation, polymorphism and inheritance that individual parts are transformed into an object; for example, it may be a car, mobile phone etc.
This is true in case of computer programs. Through object-oriented principles, the various parts of complex programs are brought together to form a cohesive, robust, maintainable whole. Many of the features supplied by java are part of its built-in class libraries which do use encapsulation, polymorphism, and inheritance extensively. Let us consider a real-world example.
Humans are a form of inheritance at one standpoint, whereas cars are more like programs we write. All drivers rely on inheritance to drive different types of vehicles.
People interface with the features on cars of all types as we have many different types of vehicles, and some have differences. The implementation of engines, brakes etc. We get a wide area of options on the same vehicle as to the anti-lock braking system, traditional braking system or power braking system. The same vehicle as many forms of the braking system is called polymorphism. This example shows us how encapsulation, inheritance and polymorphism are combined. OOPs concepts are one of the core development approaches which is widely accepted.
Some of the advantages are:. We can use it n number of times whenever required. It is one of the greatest advantages in oops. This is the condition which is created at the data storage when the same piece of data is held at two different places.
If we want to use a similar functionality in multiple classes, we can just write common class definitions for the similar functionalities by inheriting them. It is easy to modify or maintain existing code as new objects which can be created with small differences for the existing ones. It also helps users from doing rework many times.
It is time saving as we modify the existing codes incorporating new changes to it. Data hiding and abstraction are used to filter out limited exposure which means we are providing only necessary data to view as we maintain security.
The designers will have a longer and extensive design phase, which results in better designs. At a point of time when the program has reached critical limits, it will be easier to program all non oops one separately. Using encapsulation objects are self-constrained. So, if developers face any problem easily it can be solved. And there will be no possibility of code duplicity.
OOPs stands for Object-oriented programming. OOPs in Java organizes a program around the various objects and well-defined interfaces. The four basics of OOP are abstraction, encapsulation, inheritance, and polymorphism.
OOPs concepts in Java is known as object-oriented programming System. The following is a list of the OOPs concepts in Java with examples: 1. Class 2. Object 3. Inheritance 4. Polymorphism 5. Abstraction 6. Encapsulation 7. Association 8. Aggression 9. OOPs help in creating a working method and variable that can be reused without compromising on security. The reason for using OOPs concepts in Java is to implement various real-world entities such as polymorphism, abstraction, inheritance, etc.
Another reason to use this is to ensure security of code by binding together the data and functions. Java OOPs Concepts are one of the core development approaches that is widely accepted. In OOPs, Polymorphism is the process that allows us to perform a single action in multiple ways. This occurs when there are several classes related to each other through inheritance. In polymorphism, there are two types.
Namely, compile-time polymorphism and runtime polymorphism. It helps us in reducing complexity. If you found this helpful and wish to learn more such concepts, you can check out the free courses available on Great Learning Academy. Remember Me! Great Learning is an ed-tech company that offers impactful and industry-relevant programs in high-growth areas. Know More. Sign in. Log into your account. Forgot your password?
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Please enter your name here. There are people and there is a cat. They communicate with each other. It may look like this:. It also has a private method meow. What they can do is defined in the public methods sleep , play and feed.
Each of them modifies the internal state somehow and may invoke meow. Thus, the binding between the private state and public methods is made. In object-oriented design, programs are often extremely large.
And separate objects communicate with each other a lot. So maintaining a large codebase like this for years — with changes along the way — is difficult. Applying abstraction means that each object should only expose a high-level mechanism for using it. This mechanism should hide internal implementation details. It should only reveal operations relevant for the other objects. Think — a coffee machine. It does a lot of stuff and makes quirky noises under the hood. But all you have to do is put in coffee and press a button.
Preferably, this mechanism should be easy to use and should rarely change over time. You interact with your phone by using only a few buttons. You only need to know a short set of actions.
Objects are often very similar. They share common logic. So how do we reuse the common logic and extract the unique logic into a separate class? One way to achieve this is inheritance. It means that you create a child class by deriving from another parent class. This way, we form a hierarchy. The child class reuses all fields and methods of the parent class common part and can implement its own unique part. If our program needs to manage public and private teachers, but also other types of people like students, we can implement this class hierarchy.
This way, each class adds only what is necessary for it while reusing common logic with the parent classes. Say we have a parent class and a few child classes which inherit from it. Sometimes we want to use a collection — for example a list — which contains a mix of all these classes. But each child class keeps its own methods as they are.
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