Java features

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Basics and Features of Java

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Objectives

On completion of this period, you would be able to know

• The features of Java Applets and Applications

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Recap

• What is an applet?

• Differentiate Java with C++

• Why Java is important to internet?

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Features of Java applications

Sun Micro Systems officially describes Java with the following features

• Compiled and Interpreted • Platform Independent and Portable• Object Oriented• Robust and Secure• Distributed

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• Simple, Small and Familiar

• Multithreaded and Interactive

• High Performance

• Dynamic and Extensible

Features of Java applications Contd..

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Compiled and Interpreted

• Usually a computer language is either compiled or

interpreted

• Java combines both these approaches, thus making

Java a two stage system

• First Java compiler translates source code into

byte code instructions

• Byte codes are not machine instructions

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Compiled and Interpreted • In the second stage Java interpreter generates

machine code

• That can be directly executed by the machine

Contd..

Fig. 2.1 Compiled and Interpreted

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Platform Independent and Portable

• The most significant feature of Java is its

portability

• Java programs can be easily moved from one

computer system to another ,anywhere and at

anytime

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• Changes and upgrades in

• Operating systems

• Processors

• System resources

will not force any changes in Java programs

Platform Independent and Portable Contd..

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Platform Independent and Portable Contd..

Fig. 2.2 Once compiled, Java class file can be run on any platform

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Object Oriented

• Java is a true object oriented language

• Almost everything in Java is an object

• All programs code and data reside within objects

and classes

• Java comes with an extensive set of classes

arranged in packages

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Robust and Secure

• Java is a robust language

• It provides many safeguards to ensure reliable code

• It has strict compile time and runtime for data types

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• It is designed as a garbage collected language

• Java also provides concept of exception handling which identifies errors and eliminates

Robust and Secure Contd..

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• Security becomes an important issue for a

language that is used for programming on internet

• Threat of viruses and abuse of resources

• Java systems not only verify all memory access,

but also ensure that no viruses are communicated

with an applet

Robust and Secure Contd..

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• The absence of pointers in Java ensures that

programs cannot gain access to memory location

without proper initialization

Robust and Secure Contd..

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Distributed

• Java is designed as a distributed language for

creating applications on networks

• It has the ability to share both data and programs

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• Java applications can open and access remote

object as easily as they can do in a local system

• Enables multiple programmers at multiple

locations work together on a single project

DistributedContd..

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Simple, Small and Familiar • Java is small and simple language. Many features

of C and C++ are not part of Java

eg. : Java does not provide • Pointers• Preprocessors header file• goto statements• Operator overloading • Multiple inheritance

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• Familiarity is another feature of Java

• It is modeled on C and C++ languages

• Java is a simplified version of C++

Simple, Small and Familiar Contd..

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Multithreaded and Interactive

• Multithreaded means handling multiple

tasks simultaneously

• Java supports multithreaded programs

• Need not wait for the application to finish

one task before beginning another

• Greatly improves the interactive

performance of graphical applications

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High Performance

• Java performance is impressive for an interpreted

language

• Due to the use of intermediate byte code

• Java architecture is also designed to reduce

overheads during runtime

• The incorporation of multithreading enhances the

overall execution speed of Java programs

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Dynamic and Extensible

• Java is a dynamic language• Java is capable of dynamically linking new

• Class libraries• Methods • Objects

• Java programs supports functions written in other languages such as C and C++

• These functions are known as “native methods”

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• This facility enables the programmers to use the

efficient available in these languages

• Native methods are dynamically linked at runtime

Dynamic and Extensible Contd..

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Summary

• Features of Java Applications

• Features of Java Applets

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Quiz

1.Usually a computer language is either ______

a) Compiled

b) Compiled and Interpreted

c) Compiled or Interpreted

d) Interpreted

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Frequently Asked Questions

• Explain the features of Java Applications and Java

Applets

swingsStrutsjdbchibernatehomejava previous question papers OCT/NOV-2012 QUESTION PAPERApril / May 2012 c-09October/ November-2011 c-09April/ May 2011 c-09April/ May 2011 c-05

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