PGDEL/DECP03/Unit3/22

 Unit 3.3 Web application development tools &amp; Technologies  Java Java is a programming language, released by Sun Microsystems in 1995. It is the underlying technology that powers development of many programs including utilities, games, and business applications. Java runs on millions of personal computers and devices worldwide, including mobile and TV devices.

Java features

'''1. Platform independent:''' Platform independent is one of the important key features of java language makes java as the most powerful language. The programs written on one platform can run on any platform provided the platform must have the JVM.

'''2. Simple:''' Programs are easy to write and debug because java does not use the pointers explicitly. Java has the strong memory management for automatic memory allocation and deallocation. Java has the automatic garbage collection mechanism. It provides the powerful exception handling and type checking mechanism. Compiler checks the program whether there any error and interpreter checks any run time error and makes the system secure from crash.

'''3. Interpreted language:''' Java is an interpreted language as well. In interpreted language, programs run directly from the source code. The advantage of Java as an interpreted language is its error debugging quality. You can easily trace any error occurring in the program.

'''4. Object oriented:''' Java is a fully Object Oriented language because object is at the outer most level of data structure in java. No stand alone methods, constants, and variables are there in java. Everything in java is object even the primitive data types can also be converted into object by using the wrapper class. Java supports all the features of object orientated language:    • Encapsulation: provides the mechanism of combining the information and providing the abstraction.    • Inheritance: you can create the new classes and using the behavior of the existing classes by extending them just to reuse the existing code and adding the additional features as needed.    • Polymorphism: Polymorphism means one name multiple forms; Polymorphism is the way of providing the different functionality by the functions having the same name based on the signatures of the methods.    • Dynamic binding: Dynamic binding is the way of providing the maximum functionality to a program about the specific type at runtime.

'''5. Distributed:'''The widely used protocols like HTTP and FTP are developed in java. Internet programmers can call functions on these protocols and can get access the files from any remote machine on the internet rather than writing codes on their local system.

'''6. Portable:''' JVM makes the java language portable i.e. device independent. Java also has the standard data size irrespective of operating system or the processor.

'''7. Secure:''' Java does not use memory pointers explicitly. All the programs in java are run under an area known as the sand box. Security manager determines the accessibility options of a class like reading and writing a file to the local disk. Java uses the public key encryption system to allow the java applications to transmit over the internet in the secure encrypted form. The bytecode Verifier checks the classes after loading.