1. How to start programming in Java?
This part of the study material is not intended to address still concepts, but rather, you can
configure any computer window xp or Windows 7 32 or 64 bit and get it ready to start
programming.

2. METHOD 1: Use the Shell to run java code
This point is important for you to read and performers very well using the following commands:
• javac.exe, compiler generated files *. Apartir class source code (*. Java). The *. Java is text, you
can create and edit in a text editor, using the syntax of Java.
• Java.exe, systems interpreter for PC / Windows, executes bytecode files (files compiled class
extension). The *. Class have executable code, bytecode, platform independent, to be executed
on a "hypothetical or virtual machine" called Java Virtual Machine (JVM). Is this JVM neutral
who plays this code making a particular code on the CPU used. This avoids having to make a
different program for each CPU or plataforma.1
Shell enters the system and see what happens when Digitas commands: java or javac.
You will realize that the javac command is not enabled, therefore the following steps and then
try to use the command in question, the difference observed.
Remember watching the second image of this manual and look in the directory where it is
located
javac command.

3. To educate the system accepts this command indicating that we should add "environment
variables" as indicated in the graph.
Creating our first program in java
Install then an editor to start coding (in this case Notepad + +)
After that, create the following program and save it in the directory "c: ProgramasJava"
Note that the file name must be named identical to the class, using case sensitive.
Finally run the program; first compile the program with javac and then running the java
Program.

4. METHOD 2: Using the Eclipse IDE ENTERNO
(Available at www.eclipse.org - Section "downloads" download the Eclipse Classic 4.2)
This method is much faster than before, it is a method of abstraction for programming while we
should not install the JDK, and load the necessary libraries to program without tread very rodeo.
STEP 1: Download and unzip the file indicated
STEP 2: After that opening the Eclipse IDE, the program requests a folder where you will save the
projects that we believe in java, proceed as indicated in the graph (you must create the folder
previously).

5. STEP 3: Follow the following sequence of actions to create a project in java.
Look what happens next.
Now insert a class as follows

6. With the IDE, the only line of code you write play, which was noted below
Run the program with the button , watch out.
Further notes what happened in "ProgramasJava2" you created.
CLASS 2
Step by step creation of the first program in Java using Eclipse
1. Run the sequence of actions detailed in the chart.
2. Run after the sequence of actions detailed in the chart.

7. 3. Insert a class called "PruebaAlbum" as follows.
4. Now insert a class called "Album", in the same way as the previous step.
5. The result after the above steps is a structure as follows.
6. Declare the following attributes within the class "Album"

8. 7. Then set the SET and GET methods (methods are inserting, modifying and extracting the
values that variables may have happened before, "automatically generated"), this operation is
called to create getters and setters.
8. Notice how you generated the following code block without you had to write something.
9. Define the following constructor.
The constructor is a method that must have the same name as the class and is used to initialize
the attributes of an object, usually receives values have
past, a quick way is to develop a method using getters and setters
the previous step.

9. 10. Now we instantiate an object of class "Album" in class "PruebaAlbum", this instance or
reference to create should be made in the main.
See how you created two instances, and the way in which you can send arguments.
11. In the previous step we created two instances, how can we show these values on screen?
We must develop a new method in the "Album", will be called
"ImprimirAlbum"
12. Then call the method created from the two instances declared in step 10.

10. 13. And finally see the execution, after clicking on the button should appear something as
follows:
Class 3
INTRODUCTION TO JAVA CONCEPTS
Java and all Java-based trademarks are trademarks of Sun Microsystems
What is Java JDK?
JDK stands de java Developers Kit is, toolset to develop (applications) in countless classes Java.
Existent accompanying the JDK that is installed in order to get started programming in JAVA.
What makes it different from the other JAVA programming languages?
What distinguishes Java from other programming languages is its conception of departure, in
which language is to create a road that can be used to program in all types of operating systems
and processors.
One of the most important features is that the programs "executable", created by the Java
compiler, are independent of the architecture. Run interchangeably in a variety of
microprocessors and computers with different operating systems.

11. Is the language is compiled or interpreted?
Java is compiled when the source code is translated into an object called machine code (binary,
bytecode) and is interpreted because the machine code can be run on any platform which
should be an interpreter executing it in real time.
To run it, you need an interpreter, the JVM (Java Virtual Machine) Java virtual machine. Thus, it
is possible to compile the program on a UNIX workstation and run it on another Windows using
the Java virtual machine for Windows.
This JVM is responsible for reading the bytecodes and translate them into executable
instructions directly on a particular microprocessor.
The Java Virtual Machine (JVM).
The Java virtual machine is the revolutionary idea of language. It is the entity that provides
platform independence for Java programs compiled into byte-code.
Class 4
The programmer must establish the associations between the machine model "solution space"
that is where to deploy the solution, such as a computer, and the problem is what you really
want to solve "problem space" that is where the problem exists, the business.

12. What is an abstraction?
Alan kayresumion the five basic characteristics of Smalltalk for an object, the first object-
oriented language that was successful and one of the languages that is based on JAVA. These
characteristics represent a pure approach to object-oriented programming.
Everything is an object. Think of an object as a variable stores data, allows you "raise requests"
asking him to perform operations on itself. In theory, you can take any conceptual component
of the problem that is being addressed.
2. A program is a bunch of objects that tell each other what to do r
Sending messages. To make solicitude to an object, you must send a message to that object.
More specifically, you can think of a message is a request to call a method that belongs to
particular object.
3. Each object has its own memory made up of other objects. Stated another
Way, you can create a new class of Object defining a package containing existing objects.
Therefore, it may increase the complexity of a program hiding behind the simplicity of the
objects.
4. Every object has an associated type. As the saying goes, every object is an instance of a case
where "class" synonymous with "type." The most important distinguishing characteristic of a
class is "the set of messages that can be sent."
5. All objects of a particular type can receive the same messages. As discussed below, this
statement is really important. Since an object of type "circle" is also an object of type "shape," a
circle can be guaranteed to accept shape messages. This means that you can write code to
communicate with objects of type form and automatically control anything that fits the
description of a form. This capability is one of impersonation most important concepts of OOP.
Booch offers an even more succinct description of object:
- An object has state, behavior and identity.
This means that an object can have internal data (which provides state), methods (to provide a
behavior) and each object can be uniquely distinguished from other objects, ie, each object has a
unique memory address .
The object-oriented approach
Reference is made to the elements in the problem space called "objects" to their
representations in the solution space. The idea is that the program can adapt by itself to the
lingo of the problem by adding new types of objects so that when you read the code describing
the solution, you are reading words that also express the problem. Thus OOP allows you to
describe the problem in terms of the problem rather than in terms of the computer.

13. Why use classes?
Since a class describes a set of objects having characteristics (data elements) and behavior
(functionality) identical actually a class is a type of data because, for example, a floating point
number also has a set of characteristics and performance . The difference is that the
programmer defines a class to fit a problem rather than force the use of an existing data type
that was designed to represent a storage unit in a machine. You can extend the programming
language by adding new data types specific to suit your needs. The programming system
supports the new classes and provides all combinations of type providing defined types.
Creating abstract data types (classes) is a fundamental concept in object-oriented programming.
What is an object?
Once a class has been defined, you can create as many objects of that class as desired and these
objects can be handled as if the elements of the problem that is being addressed.
But how do you make a object do useful work for the programmer? There must be a way to
make an application in order to do something, such as complete a transaction, draw something
on screen or a switch.
What is an interface?
Also, each object can satisfy only certain requests. Requests can be made to an object are
defined by its interface and is the type that determines the interface. An example with the
representation of a light bulb:
The interface determines the applications that can be done to a certain object, so there must be a
code somewhere to satisfy that request. This, along with the hidden data, define what it calls the
implementation. From the standpoint of procedural programming, this is not complicated. One
type has a method associated with each possible request, and when a specific request is made to
a object, this method is called. This process is summarized by saying that the developer "send a
message" (make a request) to an object and the object knows what to do with this message (it
executes the code).
In this example, the name of the type / class is Light, the name of this particular object is lz Light
and applications that can be done to an object light is on, off, or dim glow. It has created a light
object defining a "reference" (lz) for that object and calling new to request a new object of that

14. type. To send a message to the object, defined the object name and is related to the application
of the message by a point. From the point of view of the user of a predefined class, that is the
ultimate programming objects.
The diagram above follows the format of UML (UnifiedModelingLanguage, Unified Modeling
Language). Each class is represented by a box by typing the name of the guy at the top, the data
members in the intermediate zone and methods (functions of said object receiving any message
sent to the developer that object) in the bottom . Often in these diagrams only show the name
of the class and public method, not including the buffer zone, as in this case. If you are only
interested in the class name, it is not necessary to include the bottom.
Class 5
Primitive data types IN JAVA
There are a bunch of guys that are used very often in programming and requires special
treatment. Types can be considered as "primitive", the reason for this special treatment is that
to create a new object, a simple variable small, not efficient. To these primitive types, Java uses
the technique used in C and C + +, that is, instead of creating the new variable creates a variable
"automatic" is not a reference.
Class 6
CONCEPTS OF OBJECT-ORIENTED PROGRAMMING (OOP)
1 What is OOP?
Is to develop programs from objects. These objects waiting messages, process and send
Messages to other objects. In object-oriented programming, objects are defined that make up an
application. These objects are formed by a series of features and operations that can be
performed on them.

15. 2 What is an object?
The answer to this question in terms outside the programming seems simple. An object is a
person, animal or thing. It is distinguished from other objects to have certain characteristics and
is good for something, or put another way, you can perform various operations with or on that
object. For example:
A house is an object.
OPERATIONS
Build, destroy, painted facade, modify any of the characteristics, such as opening a new window,
etc.
Obviously, each object can be defined in terms of a multitude of features and an extensive array
operations. Now in terms of programming, the programmer mission will determine what
features and interest to maintain operations on an object. For example, on the home object may
not be necessary to know its location and therefore, these features are not part of the object
defined by the programmer. The same could be said about the operations. In terminology of
object-oriented programming, the characteristics of the object are called attributes and
operations METHODS. Each of these methods is a procedure or function
belonging to an object.
An object is formed by a number of features or data (attributes) and a set of operations
(methods). No conceivable only on the basis of data or operations but as a whole.
Example: Think about what methods would be needed to make a car turn
Insert the key
Turn the key
This would trigger the electrical system
The engine ignite

16. 3. Classes and Objects
In OOP we must distinguish between two closely related concepts, the class and object.
Analogous to how to define variables in a programming language, when you declare an object
must define the type of object to which it belongs. This type is the class.
In C, we define two variables X and Y integer as follows:
Int X, Y;
In this case, X and Y are variables and the type of these variables is integer. The way to declare
objects in Java is the same:
Ccasa casa1, house2;
In this case, house2 casa1 and variables are effectively but somewhat special, are
OBJECTS. Furthermore, the type of objects is Ccasa. This type is the class of the object
Variable → Object
(X, Y) (casa1, house2)
→ Class Type
(Int) (Ccasa)
Declaring casa1 and house2 as objects belonging to the class Ccasa, it indicates that house2
casa1 and have a number of attributes (data) and are nPuertas, nVentanas and color, and also a
number of methods (operations that can be performed on them) as: abrirVentanas (),
cerrarVentanas (), etc..
4. Properties must meet to be considered a language object oriented.
POTTING
INHERITANCE
POLYMORPHISM

17. Encapsulation
Encapsulation is the property possessed objects hide their attributes, and even methods to
other parts of the program or other objects. The natural way to build
a class is to define a set of attributes which generally are not accessible outside of the same
object, but can only be modified by the methods which are defined as accessible from the
outside of that class.
Ccasa class {
int nPuertas, nVentanas; String color;
public Ccasa (int np, int nv, co String) {
nPuertas = np; nVentanas = nv, color = co;
}
public void paint (String co) {
color = co;
}
public void abrirVentanas (int n) {
nVentanas = nVentanas + n;
}
public void cerrarVentanas (int n)
{
nVentanas nVentanas =-n;
if (nVentanas <0)
nVentanas = 0;
}
public void abrirPuertas (int n) {
nPuertas = nPuertas + n;
}
public void cerrarPuertas (int n)
{
nPuertas nPuertas =-n;
if (nPuertas <0)

18. nPuertas = 0;
}
}
/ / HERE STATEMENT Ccasa casa1 objects and instances, house2;
The normal way to declare the class Ccasa is to define a set of attributes that are not accessible
from anywhere in the program, but only through certain methods. So, if you open a new
window in the house casa1, traditional philosophy of a programmer would do the following:
casa1.N_VENTANAS casa1.N_VENTANAS = + 1;
However, the natural way to do it in OOP is calling the method:
casa1.abrirVentanas (1);
That method (procedure) will increase by 1 nVentanas attribute. This does not mean that the
attribute can not be accessed nVentanas the traditional way (if it had been defined as public,
but for that language may be regarded as OOP, should allow for the possibility of prohibiting
access to the attributes directly.
Inheritance.
One of the main advantages of OOP. This property allows you to define other descendant
classes, so that the new class (the child class) inherits from the parent class all its attributes and
methods. The new class can define new attributes and methods can even redefine existing
attributes and methods (for example, change the type of an attribute or operations performed
by a given method.) Is the natural way to define objects in real life. Most people would say, for
example, that a house is a house with a garden. It has the same characteristics and properties or
operations you can perform on a house and also incorporates a new feature, the garden. At
other times, they added functionality (methods) and attributes. For example: a duck is a bird
that nothing. It has the same characteristics as the birds and should only declare a method on
the new class (the swim method).
This property enables code reuse and is very easy to take advantage of the existing class code,
modifying them minimally to fit the new specifications.
Example:
Suppose we have constructed Ccasa class and we want to define a new class that represents the
chalets. In this case you may want to define a new attribute that represents the square meters
of garden. Instead of redefining a new class from scratch, can be used for writing code Ccasa
class as follows.

19. Polymorphism
Polymorphism allows the same message to objects of different classes do these also behave
differently (different objects can have methods with the same name or the same object
methods can have identical names but different parameters)
Ccasa class {
public Ccasa (int np, int nv, co String) {
nPuertas = np; nVentanas = nv, color = co;
}
public Ccasa () {nPuertas = 0; nVentanas = 0, color = "";
}
}
You have two methods with the same name but different parameters. In the first case, the
attributes of the object initialized with the parameters of the method and in the second case will
be initialized to zero, for example. Also, if you have two objects and chalet1 casa1 and calls the
method:
chalet1.abrirVentanas (2)
Will execute the procedure code abrirVentanas Cchalet class and class Ccasa.
Class 7
'Class'
The classes are the mold for the creation of objects comprise:
 Methods. - Functions programmed to perform a certain task.
 Attributes. - Variables we will use in our program.
 Builders.
Method  main (in the case of JAVA)
In Java, almost all are classes (objects). The language requires the OOP and allows the possibility
to program using any other technique other than this. For this reason, a program will consist of
one or more source files and each will have defined one or more classes. In a source file can
declare one or more classes and will look similar to this:

20. class Class1 {
...
}
class Class2 {
...
}
Clasen class
{
...
}
A class consists of a portion of the return, and another for the body of the same:
Class Declaration
{
Class body
Class 8
Object modeling
The term object arises in the late seventies in computer science, to reference notations to
problem solving, which are apparently different but mutually linked from a perspective different
from structured analysis.
These notations define objects representing components of the modular system is decomposed
to define knowledge.
This model looks at reality as objects interacting with responsibilities, where
each object could contain internal objects to form more functionality
complex.

21. Were set out different ways to perform the analysis, design and programming, and that variety
is still present.
Object Oriented Analysis is a method of analysis to examine the requirements from a class of
objects that are searched in the vocabulary of the problem domain, in order to represent the
user experience in outlining the requirement
Object Oriented Design is a design method for understanding and process decomposition and
object-oriented notation obtaining the logical model is class and object structures and the
physical model is architecture modules and processes as well as static models and dynamic.
The Object-oriented programming is the design implementation, where programs are collections
of cooperating objects. Each object belongs to a class hierarchy, and classes belong to a
hierarchy of classes related by inheritance.
Object orientation provides elements to develop solutions based on their theory, and are those
seen in the graph.

22. What is abstraction?
An abstraction denotes the essential characteristics of an object distinguishable from other
objects and provides conceptual limits to the viewer's perspective.
When looking abstractions is necessary to focus on the important details, primarily on
similarities, differences ignoring for the moment to describe and specify some details of the
system and not go through the relevant unnoticed. A concept can be an abstraction only if it can
be described, understood and analyzed independently of the mechanisms used to achieve its
goals.
Abstractions are always influenced by the observer according to their experience and needs.
Abstraction is the recognition of the similarities between objects, situations or real -world
processes.
The abstraction focuses attention on the external view of the object to separate the essential
functioning of the object from its implementation, which is the principle of abstraction barrier.
Obtaining the abstractions of the problem domain is the core of object-oriented design, which
can be grouped into:
Class 8
What is abstraction?
An abstraction denotes the essential characteristics of an object distinguishable from other
objects and provides conceptual limits to the viewer's perspective.
When looking abstractions is necessary to focus on the important details, primarily on
similarities, differences ignoring for the moment to describe and specify some details of the
system and not go through the relevant unnoticed. A concept can be an abstraction only if it can
be described, understood and analyzed independently of the mechanisms used to achieve its
goals.

23. Abstractions are always influenced by the observer according to their experience and needs.
Abstraction is the recognition of the similarities between objects, situations or real -world
processes.
The abstraction focuses attention on the external view of the object to separate the essential
functioning of the object from its implementation, which is the principle of abstraction barrier.
Obtaining the abstractions of the problem domain is the core of object-oriented design, which
can be grouped into:
Abstraction of Bank says that an object represents a useful model of the problem domain or the
domain of a solution which has a personality.
Abstraction of Action states that an object provides a generalized set of operations which
perform the same function type
Virtual Machine states that an object abstraction grouping of operations used in an upper or
lower level control is associated with a set of common purposes verbs
Abstraction coincidental groups a set of operations or unrelated models and are associated with
a set of verbs or nouns unrelated
Every good abstraction reflects how well you manage the system vocabulary
What is encapsulation?
The abstraction of an object precedes the implementation of its services, the implementation of
an object is a secret for abstraction and should be hidden for its customers, leaving as the only
answer to their service commitment regardless of how the fix, making nowhere a complex
system depends on the implementation of some other object, edging to respect the purpose of
this abstraction
While the abstraction suggests to do, encapsulation is directed at how it will perform, allowing
programs to reliably change with minimal effort this barrier.
Encapsulation and abstraction are complementary concepts, abstraction focuses on the
operation of an object observable. The encapsulation is focused on the implementation which
gives rise to the operation.
The class of an object that is born must have two parts:
An interface for services that are related to other objects, also known as external view.
An implementation which is the implementation of services is known as internal view
The encapsulation of the idea of having a very complex system that requires much attention and
become an object that handles everything internally and can be created easily.

24. Encapsulation is a process of sharing of elements constituting an abstraction of its structure and
operation, serves to separate encapsulation of an abstract interface and implementation.
Modularity
The target an individual program components also reduces complexity of grouping a set of
components for some purpose or common feature allowing components locate efficiently
Modularity is performed to divide a system into modules separately compilable, but with certain
minimum connections dependencies with other modules.
Modularity takes care of packing abstractions in discrete units called
modules, ie the physically packaged modularization classes and objects.
By modularizing takes advantage of the cost reduction of software design and review allowing
independent modules even reuse core modules for any system.
To achieve good modularity, modules should be constructed:
Modularity is the property of a system of decomposed into a cohesive set of modules with weak
couplings.
HIERARCHY
A hierarchy is a rank or order of abstractions. A set of abstractions can repeatedly form a
hierarchy. By identifying hierarchies in the design, understanding the problem is simplified.
The hierarchy of generalization / specialization is formed by grouping abstractions within the
scheme which is a type B of A. For example, a car is a type of vehicle, is therefore to define a
relationship between classes, where a class defines the structure and behavior of one or more
classes (single inheritance and multiple inheritance respectively)

25. CONCURRENCE
Concurrency allows different objects to act simultaneously, each program has at least one child
control, but a concurrent program can have multiple threads of control: some transient and
others throughout the runtime.
The machines run on multithreaded systems truly allow concurrent threads of control
A lightweight process shares memory space with another lightweight process, while the
combination of a heavy process is assigned its own memory space.
An object-oriented system can see the real world as a set of cooperating objects concurrently,
with each active site is an independent activity center.
Concurrency is the property to distinguish an object from one active inactive in a multithreaded.
PERSISTENCE
Persistence is responsible for saving the state and the class of an object over time and / or
space.

26. Persistence is the property of an object to transcend time (the object continues to exist even
after the cessation of its creator) and / or space (the object changes its position in the memory
space that was created).
Object
From the perspective of human knowledge can be an object: Anything tangible or intangible.
Anything that can be learned intellectually.
Something toward which thought or action can be directed. An object has:
- State.
- Operation.
- Identity.
IDENTITY
Each object is unique, even though sharing the same properties of another object, since it
occupies a different space. That is, an object has an authenticity identidad.This shown in the
variable of time and space.
Identity is the property of an object to be distinguished from all other objects.

27. Relationships between objects
When multiple objects relate these make assumptions about each other, including the methods
performed well as the state of operation. The hierarchy of objects are of two types:
INTERFACE AND IMPLEMENTATION
If a class is segmented this can have two views, one internal and one external, the external form
its interface while the inner shape its implementation
The interface of a class provides an outside view and emphasizes the abstraction while hiding
the secrets of the structure and functioning. Initially is to declare all methods applicable to
instances of that class, the statement may also be included in other classes, constants, variables,
and exceptions, ie properties necessary to complete abstraction.
The implementation of a class provides the internal view, which covers the "secrets" of the
operation. The implementation of a class is to implement all the methods defined in the
interface.
A class interface basically consists of three parts:
PUBLIC: Statements available to all customers.
PROTECTED: Statements accessible only to its class, its subclasses and their friends.
PRIVATE: Statements accessible only to the class and their friends (friends refers to what is in
the class and its methods).
Relationships between classes
In particular, the problem domain abstractions relate obtained in different ways, the totality of
these relations are known as class structure. Relations between two classes have two main
reasons:
A list of classes may indicate the hierarchical share some characteristics. A list of classes may
indicate some connection semantics.

28. There are three basic types of relationships:
Generalization / specialization. In this, two classes are linked by the relationship
Total / Party. Two classes are linked by the relation "part of"
Association. Two classes are linked by descent semantics
Programming languages, specifically object-oriented, providing direct support for some
combinations of the following relationships:
Association. The association denotes a semantic dependence, ie, their relationship is applied in
concept and is not required to encode physical dependence.
The association is named after the link through which bind classes and indicates a direction to
hear the reading direction of the association for their classes.
At the time of analysis are extremely useful to indicate dependencies, without elaborating. An
association has a cardinality between parts to indicate the number of classes associated with
another number of classes
Inheritance.
For there must be an inheritance subclass can inherit the structure and operation of its
superclass.
Inheritance is the relationship between classes, where one class shares the structure and / or
function defined in a class (single inheritance) or more classes (multiple inheritance).
The class to inherit property is called superclass and inherited class is called subclass.
A subclass can increase or restrict the structure and operation of its super class. When a subclass
increases its superclass is said that "inherited by extension".
When a superclass is designed to group functionality and structure, but not designed to create
instances is called abstract class.

29. IDENTIFICATION OF CLASSES AND OBJECTS
Historically there are three basic approaches to classify:
No classification is absolute, because some structures can be mostly favored classes of one
application to another, no classification scheme represents the actual structure or the natural
order. Some classifications may be more significant over other as our interest but not represent
reality more accurately or adequately but to serve our purposes
Classification classic. - All entities with a property or collection of properties common form a
category, the traditional classification comes from Plato, Aristotle then, by means of classifying
plants and animals, and to find answers to questions like: Is animal? Is Mineral? Is it vegetable?
One thing can be named according to the knowledge gained from the nature of their properties
and effects, the practical approach using real estate as a criterion of similarity between objects,
specifically objects can be grouped into sets depending on the presence or absence of a
particular property
Conceptual clustering. - It is a modern variation of the classical approach of trying to explain
derivative knowledge, this approach class or group of entities is generated to make the first
conceptual description of the class. The long tapering conceptual clustering with fuzzy theory in
which objects belong to one or more groups of attitudes varying degrees, depending on the
classification considers the functionality of their bodies.
The traditional classification and conceptual clustering are sufficient to explain most complex
designs classifications
Prototype theory. - Is derived from the use of cognitive theory, if we try to classify games and
they can not be properly represented by the classical mold by not sharing similar properties all
games, however the team's theory unifies game ratings as family resemblances. An object class
is represented by a prototype object and an object is considered a member of that class if and
only if it is similar to the prototype significantly.

30. Instead prototype theory unifies the classification of games as family resemblances, an object
class is represented as an object prototype and an object is considered a member of this class if
and only if it is similar to the prototype significantly.
Currently these three classification approaches have direct application to object-oriented
design.
CLASS 9
Primitive Data Types in Java
A data type is an attribute or characteristic that is the data-this serves to tell the computer what
kind of information to be processed, for example, what values can take and what operations can
be performed with them. The most common data types are: integers, floating point numbers
(decimal), strings, dates, times, colors, etc.. Below is a table of the most primitive data types
used, and a description of each.
Boolean
ie values that can be true or false. Occupies 1-bit and the default value is false char
The characters are 16-bit and are encoded in Unicode 1.1.5, in other languages are only 8-bit
ASCII. Occupies 16-bits
byte
unsigned 8-bit integer, ie the fewer number (two to the seventh) and two in the eighth. The
internal representation is in 2's complement
Short
unsigned 16-bit integer. The internal representation is in 2's complement int
unsigned 32-bit integer. The internal representation is in 2's complement
Long
unsigned 64-bit integer. The internal representation is in 2's complement float
32-bit real mobile with coma. The internal representation is IEEE 754-1985. doublé
32-bit real mobile with coma. The internal representation is IEEE 754-1985.
Each primitive type has an associated class, you can store the same information but always
through objects.