What is Java ? and Features of JAVA

Java features

What is Java?

u Java is a programming language that:

n  Is exclusively object oriented

n  Has full GUI support

n  Has full network support

n  Is platform independent

n  Executes stand-alone or “on-demand” in web browser as applets

Features of JAVA

1. Simple
2. Secure
3. Portable
4. Object-oriented
5. Robust
6. Multithreaded
7. Architecture-natural
8. Interpreted
9. High performance
10. Distributed
11. Dynamic

1. Simple

v  Java was designed to be easy for the professional programmer to learn and use effectively.

v  Assuming that you have some programming experience, you will not find java hard to master.

v  If you already understand the basic concepts of object oriented programming, learning java will be even easier.

v  If you are an experienced C++ programmer, moving to java will require very little effort. Because java inherits the C/C++ syntax and many of the object oriented features of C++, most programmers have little trouble learning Java.

2. Security

v  Security is the benefit of java. Java system not only verifies all memory access but also ensure that no viruses are communicated with an applet.

      3. Portable

      The most significant contribution of java over other language is its portability.

      Java programs can be easily moved from one computer system to another.

      Java ensures portability in two ways:

      1. Java compiler generates byte code instruction that can be implemented on any machine.

      2.   The size of the primitive data types is machine-independent.

4. Object-Oriented

vJava is a true object oriented language. All program code and data reside within object       and classes. The object model in java is simple and easy to extend.

5. Robust(healthy, strong)

v  The multiplatform environment of the Web places extraordinary demands on a program, because the program must execute reliably in a variety of systems. Thus, the ability to create robust programs was given a high priority in the design of java.

v  To gain reliability, java has strict compile time and run time checking for codes.

v  To better understand how java is robust, consider two main reasons for program failure: memory management mistakes and mishandled exceptional conditions.

6. Multithreaded

v  Java was designed to meet the real-world requirement of creating interactive, networked programs.

v  To accomplish this, java supports multithreaded programming, which allows you to write programs that do many things simultaneously.

v  The java run-time system comes with an elegant yet sophisticated solution for multiprocess synchronization that enables you to construct smoothly running interactive systems.

v  Java’s easy to use approach to multithreading allows you to think about the specific behavior of your program, not the multitasking subsystem.

7. Architecture-Neutral

v  A central issue of java programmers was that code longevity and portability. One of the main problems facing programmers is that no guarantee exists that if you write a program today, it will run tomorrow- even on the same machine.

v  Operating system upgrades, and changes in core system resources can al combine to make a program malfunction.

v  The java designer made several hard decisions in the java language and the java virtual machine in an attempt to alter this situation. Their goal was “write once; run anywhere, any time, forever.”

8. Interpreted

v  Usually a computer language is either compiled or interpreted. Java combines these approaches thus making java a two-stage system.

v  Java compiler translates source code into byte code instructions. Byte codes are not machine instructions and so java interpreter generates machine code that can be directly executed by the machine that is running the java program.

v  We can thus say that java is both a compiled and an interpreted language.

9. High Performance

Java performance is impressive for an interpreted language, mainly due to the use    of intermediate byte code.

10. Distributed

v  Java is designed for the distributed environment of the Internet, because it handles TCP/IP protocols.

v  Java also supports Remote Method Invocation (RMI). This feature enables a program to invoke methods across a network.

11. Dynamic

v  Java is capable of dynamically linking in new class libraries, methods and object.

v  Java can also determine the type of class through a query, making it possible to either dynamically link or abort the program.