introduction to java, history and features

What is Java? And Why Java? 

                            Java is a general-purpose, concurrent, class-based, object-oriented computer programming language. Java is an open-source Software. It is intended to let application developers "write once, run anywhere" (WORA), meaning that code that runs on one platform does not need to be recompiled to run on another. 

                            Java applications are typically compiled to bytecode (class file) that can run on any Java virtual machine (JVM) regardless of computer architecture. Java is, as of 2012, one of the most popular programming languages in use, particularly for client-server web applications, with a reported 10 million users. 

                           

                            Java was originally developed by James Gosling at Sun Microsystem's (which has since merged into Oracle Corporation) and released in 1995 as a core component of Sun Microsystem's Java platform. The language derives much of its syntax from C and C++, but it has fewer low-level facilities than either of them. 

Java available as

JavaSE :- Java Standard Edition(for standalone applications development)

JavaEE :- Java Enterprise Edition (for Enterprise level applications development)

JavaME :- Java Micro Edition(for Mobile applications development)

Java features:- 

1. Simple 
2. Object Oriented
3. Platform Independence
4. Portability
5. Interoperability
6. Secure
7. Automatic Memory Management
8. Multi-threaded language
9. Dynamic and extensible
10. Distributed......etc

History  Of  Java  

1. JAVA is developed by ‘JAMES GOSLING’.

2. In 1990’s ‘JAMES GOSLING’ and his team members working in ‘OAK TECHNOLOGIES’ present in ‘US’.

3. They are assigned a project a web project .

4. They started the project with the help of c++ Lang and after compilation of 30% of the project; they observed that huge problems while developing so they stopped the project and searching for other lang which is suitable for this.

5. Finally they decided to devolope one new lang ---named  ‘OAK’ lang.

                 OAK=  c++ - complexity + new features.

6. By using this lang they completed  100% of the project.

7. In 1992, SUN-MIRO-SYSTEM’s bought the copyrights of OAK lang and hires JAMES GOSLING’ and his team into it.

8. The SUN-MIRO-SYSTEM people to change the name of ‘OAK’ lang to “JAVA”  in 1995.

9. They released the first version of JAVA  in 1996 jdk1.0, 1.2 -----1.7(jul2011).

10. They given java in JavaSE , JavaEE , JavaME flavours .

  Java  Features  Or   Buzz Words

1. Object Oriented

    - Java is an Object oriented prog-lang.

    - Java supports classes & objects concepts.

2. Simple

 Java consists of all the methods and features which are related to real world.

For ex:--in c++ we use cin & cout for input and output,

Which may  not understandable to all! But in JAVA we use print() which is easy to know.

3. Portable & Platform Independent

JAVA can run in any OS (windows, Mac, Linux etc),So we call it as Platform independent.

4. Robust

Means Strong. Compare to other languages JAVA uses BYTECODE verifier to verify each bit when it is executing.

 In c & c++ the files converts into: ---

  .c---->.obj--à .exe.

In exe files anybody can inject virus, so no security where as in JAVA it relies on BYTECODE so no question of  VIRUS.

5. Multithreaded

We can run number of processes at a time. Means we can execute multiple tasks at a time concurrently.

6. Interoperability

Java can integrate with other languages easily.

7. Secured

The binary form of programs running on the Java platform is not native machine code but an intermediate bytecode. The JVM performs verification on this bytecode before running it, to prevent the program from performing unsafe operations

8. Automatic Memory Management

 JAVA inbuilt have Garbage Collector to destroy unreferenced/unused  memory from the application to improve the performance of the application execution.This garbage collector will automatically  manages the memory in java.....etc