To all java experts - can somebody please define abstractation and encapulation in java with examples - Thanks

If you really want to learn stuff about java, i suggest u lay your hands on books like: thinking in java, or java how to program, They're available in pdf

Please can you send me the pdf version of java how to program? Prefarably the 7th edition but if that is not available, you can send me any other edition of the book. u can upload it or send it to my e-mail. marvelindaclub@yahoo.com

blacksta:

To all java experts  - can somebody please define abstractation and encapulation in java with examples - Thanks

Abstraction and Encapsulation are quite similar and confusing when you start oops programming, but heres my explanation:

Abstraction means hiding the internal details and just exposing the ‘relevant’ functionality (i.e. the interface). For Example:-When you change the gear of your car, you know the gears will be changed without knowing how they are functioning internally. Now I have not coded in Java for about a year  but from the top of my head:

public interface GearBox
{
int gearOne();
int gearTwo();
int gearThree();
int gearFour();
int gearFive();
int reverse();
int neutral();
}

Encapsulation refers to the transparency of an object - information hiding. By hiding the information inside an object we prevent a client from making unauthorized modifications, why? it makes code more robust. For example:

public class NaijaCar extends Car implements GearBox
{
public NaijaCar() {  //init code here }

private double acceleration = 1.0;

//Now implement the interface

public int gearOne()
{
super.speed += acceleration;
}

public int gearTwo() {
super.speed += acceleration * 2.0;
}
//And so on for gear 2,3 and 4
public int gearFive()
{
super.speed += acceleration * 5.0;
}
public int reverse()
{
super.speed -= acceleration;
}
public int neutral()
{
super.speed = 0.0;
}
}

So you can see the Abstraction in the sense that users of NaijaCar use all mthe relevant gearbox methods without knowing the deatils of how each one works. some homework for you, where is the encapsulation in NaijaCar?

As an object oriented programmer their are 4 principles or pillar you will need to understand and the rest is history

Pillar #1: Encapsulation
Pillar #2: Inheritance
Pillar #3: Polymorphism
Pillar #4: Abstraction - some argue you only have the 3 top pillars


would anybody please give defination for the above  - thanks

also thanks to Linxon ( wonderful example)

u bumped the thread right. 

in ur last post you listed 4 core oo principles. Just  to add also that it is good oo practice to favor Encapsulation vs Inheritance cos it allows for very flexible oo designs

Abstraction is definitely an OOP basic.

Helloooo

am about using Netbeans for Java programming. I would like to know if its like Visual Basic.net.

thanks

Abstraction - from the word abstract - meaning overview - As an analogy, when you read a technical document. There's always an abstract which gives a general overview of what the document is about.

In Object Oriented programming, Abstraction gives the specification of an Interface. i.e it gives the Name of the interface and the names of all the methods in the interface but not the details. Any class that plans to implement that interface must use the specified methods. You make use of the specified methods but you supply the details in each method yourself.

Encapsulation on the other hand refers to the fact that the when a user uses an object of a class, he has no ability to change the inner operations of the class methods and variables. That is the internal operations of the class is shielded protected or encapsulated.

Inheritance is the relationship between two classes that allows an object of one class called the sub class to use the methods already defined in another class called the super class. The syntax is

Class Subclass extends Superclass
For example

Class Vehicle{

accelerate();
reverse ();
changeGear();

}

Class SUV extends Vehicle{

// no need to specify the accelerate(). reverse(); and changeGear() methods. (except during method overriding)

}

Class Vehicle is the superclass while class SUV is the subclass. Class SUV inherits the methods of class Vehicle, therefore if you create an object of Class SUV and make it inherit from class Vehicle, you can call the methods of the superclass Vehicle without having to define them in the SUV object.
The primary purpose of inheritance is code reuse. i.e you don't have to keep defining methods for each object you create.

akinwunmi:

Helloooo

am about using Netbeans for Java programming. I would like to know if its like Visual Basic.net.

thanks

No where near as good as Visual Studio am afraid.

Hello. pls kindly assist me with this prob.
I am introducing a password page to an application. But i'm stock in between pls cam somebody help me on how to go about it

;d

linxon:

Abstraction and Encapsulation are quite similar and confusing when you start oops programming, but heres my explanation:

Abstraction means hiding the internal details and just exposing the ‘relevant’ functionality (i.e. the interface). For Example:-When you change the gear of your car, you know the gears will be changed without knowing how they are functioning internally. Now I have not coded in Java for about a year  but from the top of my head:

public interface GearBox
{
int gearOne();
int gearTwo();
int gearThree();
int gearFour();
int gearFive();
int reverse();
int neutral();
}

Encapsulation refers to the transparency of an object - information hiding. By hiding the information inside an object we prevent a client from making unauthorized modifications, why? it makes code more robust. For example:

public class NaijaCar extends Car implements GearBox
{
public NaijaCar() {  //init code here }

private double acceleration = 1.0;

//Now implement the interface

public int gearOne()
{
super.speed += acceleration;
}

public int gearTwo() {
super.speed += acceleration * 2.0;
}
//And so on for gear 2,3 and 4
public int gearFive()
{
super.speed += acceleration * 5.0;
}
public int reverse()
{
super.speed -= acceleration;
}
public int neutral()
{
super.speed = 0.0;
}
}

So you can see the Abstraction in the sense that users of NaijaCar use all mthe relevant gearbox methods without knowing the deatils of how each one works. some homework for you, where is the encapsulation in NaijaCar?

public class NaijaCar extends Car implements GearBox
{
public NaijaCar() {  //init code here }

private double acceleration = 1.0;

//Now implement the interface

public int gearOne()


The field decleared private cant not be accessed by anyone outside of the class

@blacksta
Seeing U r a java programmer.
I nid ur help.
I am making a career change in2 programming, so I nid all d help I can get.
I am hoping U nd others alike will b of assistance 2me.
Pls, i wud b grateful if U cud assist me with some Java ebooks 4beginners nd also d compiler or U cud just paste d sites/links whr I can dwnld them 4rm.
Thanks.

Helo people.plx can i get d rough estimate of being a sun java certified programmer/developer and how long it takes to run the programme,all tins being equal.tanx

@ iceman, pls how can i get pdf on how to progran java, pls send it to my netfreakz@gmail.com. tnx

Pls anyone with useful info to my questn shld pls email me-evagreenfields@gmail.com

Evagreenfields:

Helo people.plx can i get d rough estimate of being a sun java certified programmer/developer and how long it takes to run the programme,all tins being equal.tanx

Are u talking about a self study route or Attending a college >

Self study,@blacksta,i just want to read up java programming books and then sit 4 the programming exam,

Hello All
@Blacksta, plz can u help me out with this assignment.

How java handles graphic and example of simple program to effect it.

post it here or u can send it to my mail bloomstech@yahoo.com

waiting for ur reply.

Thanks

hello moderator and all nairaland fan,i'm a graduate of mathematics/computer sci. After my graduation i decide 2 learn JAVA programming to boost my knowledge.but the language is difficult.i hav decide 2 pick it up,4rm 2moro.i need help my email is bluediva555@yahoo.com,pls if u hav any codes 2 assist me i'll be glad.

Data abstraction means hiding some data elements of a class from the public

class Student
{
private String regNo;
private String name;

public void setRegno(String regNo)
{
this.regNo= regNo;
}

public String getRegno()
{
return regNo;
}

public void setName(String name)
{
this.name= name;
}

public String getName()
{
return name;
}

}

Hoope this explains the concept

uche1:

How java handles graphic and example of simple program to effect it.

Familiarize yourself with the Java 2D API. It's a whole lot of package. You'll see lots of (hands-on) examples while learning!!!

Visit http://www.corewebprogramming.com/PDF/ch10.pdf for Java 2D tutorial.

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The legendary author Bruce Eckel brings Java to life with this extraordinarily insightful, opinionated and downright funny introduction. Thinking in Java introduces all of the language's fundamentals, one step at a time, using to-the-point code examples. More than virtually any other book, Thinking in Java helps you understand not just what to do -- but why. Eckel introduces all the basics of objects as Java uses them; then walks carefully through the fundamental concepts underlying all Java programming -- including program flow, initialization and cleanup, hiding implementations, reusing classes and polymorphism. Using extensive, to-the-point examples, he introduces error handling, exceptions, Java I/O, run-time type identification, and passing and returning objects. He covers the Java AWT, multithreading, network programming with Java -- even design patterns. The best way to understand the real value of this book is to hear what readers of the online version have been saying about it: "much better than any other Java book I've seen, by an order of magnitude, " "mature, consistent, intellectually honest, well-written and precise, " "a thoughtful, penetrating analytical tutorial which doesn't kowtow to the manufacturers, " "Thank you again for your awesome book. I was really floundering, but your book has brought me up to speed as quickly as I could read it!"For both beginner and experienced C and C++ programmers who want to learn Java.

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If u need more books or certification exam notes let me know

@blacksta, pls can i get a book for newbie programmers

ikmomen:

@blacksta, pls can i get a book for newbie programmers

Try the head first Java series very good for newbies

head first what of mouth first