Page 65 - Viva ICSE Computer Studies 8 : E-book

However, a computer cannot perform these functions on its own. It needs a set of instructions
called programs. These programs are translated into machine codes by a translator (interpreter
or compiler). A program written in a human readable form is known as source code whereas
the program converted by the translator into a form that a computer understands is known as
object code. The language used to write these instructions is called programming language
and the person who creates these programs is known as a programmer.

Introduction to Java
In this ever-changing time of networks and Internet, Learn More
all the applications being developed must have a
Java was developed in January 1996
global outlook. Software that works anywhere on any
by a team of Sun Micro systems,
platform and with any applications are the need of headed by James Gosling.
the hour. The Java programming language is a ‘Write
Once Read Anywhere’ language. This indicates that a Java program written on one computer
will also run on any other computer even when the hardware confi guration or the operating
system is diff erent.

Java is an object-oriented programming language. It is also used as a language for creating
Internet-based applications. Most of the applications that we download on mobile phones for
Internet gaming are developed in Java.

Introduction to BlueJ and Its Features

BIueJ is an Integrated Development Environment (IDE) for beginners to write, edit and execute
Java programs. BlueJ allows beginners to write programs in such a way that gives them a grasp
over the concepts. It includes the following elements.
Learn More
A viewer: It is used to view parts of a program.
An editor: It is used to write the programs. BIueJ is a Java development
environment that is being
A debugger: It helps to fi nd the mistakes in a program. developed and maintained

BlueJ also includes an easy way to run JAVA programs and by a joint research group at
view documentation. Deakin University, Melbourne,
Australia, and the University
Object of Kent in Canterbury, UK.

An object is a real-world entity. It can be a living thing (like cat, dog, plant) or a non-living thing
(like pen, paper, board).

These real-world objects have two characteristics: state and behavior. State determines the
properties, appearance, and other related features. Behavior determines what the object really
does. For example, dogs have state (name, color, breed) and they have behavior (barking,
fetching). Bicycles have state (two wheels, number of gears) and behavior (braking, accelerating,
slowing down, changing gears). Software objects are modeled after real-world objects. They
too have state and behavior. A software object maintains its state in variables and implements
its behavior with methods.

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