What is the use of encapsulation in java?

Answer 1

The ability to make changes in your code without breaking the code of all others who use your code is a key benefit of encapsulation. You should always hide implementation details. To elaborate, you must always have your variables as private and then have a set of public methods that others can use to access your variables. Since the methods are public anyone can access them, but since they are in your class you can ensure that the code works the way that is best for you. So in a situation that you want to alter your code, all you have to do is modify your methods. No one gets hurt because i am just using your method names in my code and the code inside your method doesnt bother me much.

If you want maintainability, flexibility, and extensibility (and I guess, you do), your design must include encapsulation. How do you do that?

• Keep instance variables protected (with an access modifier, mostly private).

• Make public accessor methods, and force calling code to use those methods rather than directly accessing the instance variable.

• For the methods, use the JavaBeans naming convention of set and get.

source- SCJP book by Kathy and Bert

Answer 2

Well to be conceptual of encapsulating data in Java the importance of Encapsulation. Not only does this hide the details of the code but has a capability of dynamicly changing or binding the data. It works together with the interfaces of groups of related methods with empty bodies such as behaviors and shares the common state of these behaviors from other class objects or set of plans that can be used to construct objects. A Java object is an instance of the class declared and the variables are assigned the name and encapsulation is the concept that an object should totally separate its interface from ists implementation. All the data and implementation code for the object should be entirely hidden for it interface. Meaning that its become private from change after coded and the idea is that we can create an interface method in a class and as long as the interface remains consistent and interact with the objects. This remains true evenif we entirely rewrite the code with in a given method thus the interface is independent of the implementation. Remember that encapulation means that the attributes (data) and the behaviors (code) are encapsulated into a single object. Known as abstract data with persistence,state,massage,method and behaviors in the super object with the ability to store data,modify data, and manipulate it. last of all immutable data is unable to be changed unless it become accessibe to the outside world.

Answer 3

Encapsulation refers to hiding the internal details of how a class works - making them inaccesible from outside of the class. The idea is to allow making changes within a class, without breaking compatibility with code that uses that class. The class interface - the way the class methods are called - would not change in this case, even if internal details in the class do change.

Answer 4

Encapsulation is a key concept of all object-oriented programming languages. An object should encapsulate all the information required in order to use the object. That is, the object's physical representation and underlying implementation can be largely or wholly hidden from the user, exposing an interface that ensures the object remains in a valid state throughout its life-cycle. The object should be completely self-contained and should not rely or depend upon other objects, other than those it uses and depends upon internally.

Answer 5

The ability to make changes in your code without breaking the code of all others who use your code is a key benefit of encapsulation. You should always hide implementation details. To elaborate, you must always have your variables as private and then have a set of public methods that others can use to access your variables. Since the methods are public anyone can access them, but since they are in your class you can ensure that the code works the way that is best for you. So in a situation that you want to alter your code, all you have to do is modify your methods. No one gets hurt because i am just using your method names in my code and the code inside your method doesnt bother me much.

Answer 6

Imagine that we both work for the same project and first you wrote the code for a class, and then I used your class in my program. Later on, you didn't like the way the class behaved, because some of its instance variables were being set (by me from my code) to values you hadn't anticipated. Their code brought out errors in your code. (Relax, I wont do that, dont worry.) Since, it is a Java program, so you should be able just to ship out a newer version of the class, which I could replace in my programs without changing any of my own code.

The above scenario highlights two of the promises or rather i should say benefits of Object Orientation (OO): flexibility and maintainability. But these benefits will not come automatically. You have to do something. You have to write your classes and code in a way that supports flexibility and maintainability. Just because Java supports OO concepts, it cannot write code for you. Can it?? For example, imagine if you made your class with public instance variables, and those other programmers were setting the instance variables directly, as the following code demonstrates:

public class BadExample {

public int size;

public int weight;

...

}

public class AnotherBadExample {

public static void main (String [] args) {

BadExample b = new BadExample ();

b.size = -5; // Legal but bad!!

}

}

Now go back the scenario we spoke about a paragraph ago. BadExample is your class and AnotherBadExample is my code. I have modified one of your variables in a way that it helps my code logic but that totally alters the way your class works. Now you are in trouble. How are you going to change your class in such a way that no one can alter your values directly (like what i have done in my code)? Your only choice is to write a method say setSize(int newVal) inside your class and then change the access modifier of the variable size to say, private. This will ensure that you handle instances when someone is trying to set a value to the size variable that you dont want and at the same time ensure that no one can access the size variable directly and mess with your code.

But, unfortunately, by doing that, you have broken my code. If I try to compile my AnotherBadExample class, i will get errors because the size variable is no longer visible for me.

How can we address this situation now? The best way is: not write such code where public variables are available for anyone and everyone to modify.

The ability to make changes in your code without breaking the code of all others who use your code is a key benefit of encapsulation. You should always hide implementation details. To elaborate, you must always have your variables as private and then have a set of public methods that others can use to access your variables. Since the methods are public anyone can access them, but since they are in your class you can ensure that the code works the way that is best for you. So in a situation that you want to alter your code, all you have to do is modify your methods. No one gets hurt because i am just using your method names in my code and the code inside your method doesnt bother me much.

If you want maintainability, flexibility, and extensibility (and I guess, you do), your design must include encapsulation. How do you do that?

• Keep instance variables protected (with an access modifier, mostly private).

• Make public accessor methods, and force calling code to use those methods rather than directly accessing the instance variable.

• For the methods, use the JavaBeans naming convention of set and get.

Answer 7

It means that a single thing encloses several smaller things that are it's part. The wrapping up of data and functions into a single unit is known as encapsulation.

Answer 8

The following things required to implement encapsulation in Java

1) Make all variables private and only allow access via methods

Answer 9

primitive data