Introductionto

java

About java:-• Appeared in 1995

• Designed by James gosling & sun microsystem

• Developer oracle corporation

• Stable release java standard edition 7 update40

(1.7.40) 10 September 2013

• Typing discipline static ,strong, safe nominative,

manifest

• Major implementations open jdk many other

• Dialects generic java ,pizza

• Implementation language c & c++

• Os cross plateform(multiplatform)

• License gnu general public license , java community process

• Usual file name extension .java,.class,.jar

History of java:-Major web browsers soon incorporated the ability to run Java applets within web pages,

and Java Mike Sheridan, and Patrick Naughton initiated the Java language project in June

1991. Java was originally designed for interactive television, but it was too advanced for

the digital cable television industry at the time.The language was initially called Oak after

an oak tree that stood outside Gosling's office; it went by the name Green later, and was

later renamed Java, from Java coffee said to be consumed in large quantities by the

language's creators. Gosling aimed to implement a virtual machine and a language that

had a familiar C/C++ style of notation.

Sun Microsystems released the first public implementation as Java 1.0 in 1995. It

promised "Write Once, Run Anywhere" (WORA), providing no-cost run-times on

popularplatforms. Fairly secure and featuring configurable security, it allowed network-

and file-access restrictionsquickly became popular.

Today, with technology such a part of our daily lives, we take it for granted that we can be

connected and access applications and content anywhere, anytime. Because of Java, we expect

digital devices to be smarter, more functional, and way more entertaining.

In the early 90s, extending the power of network computing to the activities of everyday life was a

radical vision. In 1991, a small group of Sun engineers called the "Green Team" believed that the

next wave in computing was the union of digital consumer devices and computers. Led by James

Gosling, the team worked around the clock and created the programming language that would

revolutionize our world – Java.

The Green Team demonstrated their new language with an interactive, handheld home-

entertainment controller that was originally targeted at the digital cable television industry.

Unfortunately, the concept was much too advanced for the them at the time. But it was just right

for the Internet, which was just starting to take off. In 1995, the team announced that the

Netscape Navigator Internet browser would incorporate Java technology.

Today, Java not only permeates the Internet, but also is the invisible force behind many of the

applications and devices that power our day-to-day lives. From mobile phones to handheld

devices, games and navigation systems to e-business solutions, Java is everywhere!

On May 8, 2007, Sun finished the process, making all of Java's core code available under free

software/open-source distribution terms, aside from a small portion of code to which Sun did not

hold the copyright.

Sun's vice-president Rich Green said that Sun's ideal role with regards to Java was as an

"evangelist." Following Oracle Corporation's acquisition of Sun Microsystems in 2009–2010,

Oracle has described itself as the "steward of Java technology with a relentless commitment to

fostering a community of participation and transparancy".This did not hold Oracle, however,

from filing a lawsuit against Google shortly after that for using Java inside the Android SDK (see

Google section below). Java software runs on everything from laptops to data centers,game

consoles to scientific supercomputers. There are 930 million Java Runtime

Environment downloads each year and 3 billion mobile phones run Java. April 2, 2010, James

Gosling resigned from Oracle.

Why java:-

Simple- Java has thrown out many of the complex features of C++ and C resulting

in a simpler language (no pointers, no unions, no enumerations) .

Object-oriented - Java is a single-root, single-inheritance object oriented language .

Multithreaded - Java has a built-in support for multithreading .

Distributed - Using Java RMI (remote method invocation) you can access objects on

other machines almost as if they were local .

Portable - programs written in the Java language are platform independent.

Java is object-oriented. Unlike languages, such as FORTRAN, which focus on

giving the computer imperative "Do this/Do that" commands, object-oriented

languages focus on data. Of course, object-oriented programs still tell the

computer what to do. They start, however, by organizing the data, and the

commands come later.

Object-oriented languages are better than "Do this/Do that" languages

because they organize data in a way that lets people do all kinds of things with

it. To modify the data, you can build on what you already have, rather than

scrap everything you've done and start over each time you need to do

something new. Although computer programmers are generally smart people,

they took awhile to figure this out.

Object oriented in java:-

Data Moving:-

In POP, Data can move freely from function to function in the system.

In OOP, objects can move and communicate with each other through member

functions.

Expansion:-

To add new data and function in POP is not so easy.

OOP provides an easy way to add new data and function.

Data Access:-

In POP, Most function uses Global data for sharing that can be accessed freely from

function to function in the system.

In OOP, data can not move easily from function to function ,it can be kept public or

we can control the access of data.

Data Moving:-

In POP, Data can move freely from function to function in the system.

In OOP, objects can move and communicate with each other through member

functions.

Expansion:-

To add new data and function in POP is not so easy.

OOP provides an easy way to add new data and function.

Data Access:-

In POP, Most function uses Global data for sharing that can be accessed freely from

function to function in the system.

In OOP, data can not move easily from function to function ,it can be kept public or

we can control the access of data.

Data Hiding:-

POP does not have any proper way for hiding data so it is less secure.

OOP provides Data Hiding so provides more security.

Overloading:-

In POP, Overloading is not possible.

In OOP, overloading is possible in the form of Function Overloading and Operator

Overloading.

Examples:-

Example of POP are : C, VB, FORTRAN, Pascal.

Example of OOP are : C++, JAVA, VB.NET, C#.NET.

Types of java:-

• Advance java

• Core Java

Any question ?

BY:-Sanjeev kumar singh

Cs 2nd year

HIET (GHAZIABAD)