JAVA Introduction
Java is an Object Oriented and Multithreaded Programming Language. It was developed by Sun Micro Systems in 1991. Initially the name was called OAK, which was renamed Java in 1995. It is designed by simple, small and portable access operating systems.
Java is designed on the three basic elements.
They are usage of Applets, powerful programming language constructs, and sets of object classes.
Java environment is divided into two categories:
Java Compiler and Java Interpreter
The Java compiler generates the byte code instead of the machine code.
The Java interpreter executes the Java program.
The disadvantage of the byte code is the execution speed. Since the system specific programs run directly on the hardware, they are faster than Java byte code, which is processed by the interpreter.
The editor can be Notepad, WordPad, MS-DOS Editor etc
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It is a Platform Independent Language.
Java is “write once and run anywhere”.
Java source code is compiled on Windows and can be run on UNIX without recompilation
Features of Java
Simple and Powerful
Java was designed to be easy for the programmer to learn and use effectively. It exhibits the inner workings of a machine. The programmer can perform easily without any fear. Unlike other programming languages, which provides complicated ways to perform a single task, Java will be very easy.
Secure
Nowadays, everyone is worried about safety and security. The threat of viruses and system hackers also exists. To overcome this hurdle, Java is safe and secure to use.
Portable
The same mechanism, which gives security also helps in the portability. Many types of computer and operating systems are used in the world and are connected to the internet.
Object Oriented
Java was not designed to be a source code compatible with any other language. Java team members gave usable and realistic approaches to the object. The object model in Java is simple and easy to extend.Robust
Most programs in use today fail for one of two reasons: Memory Management and Run Time Errors.
Of the two reasons for the program failure (memory management and run time errors), Memory management is very easy – de allocation is done by garbage collection and run-time error is very easy – exception handling mechanism is used.
Multithreaded
Java was designed to meet the real world requirements of creating an interactive, networked program. Java supports multithreaded programming, which allows the user to write the programs, which perform many functions simultaneously.
Architecture neutral
Java designers worked hard in attending to the goal “write once and run anywhere, anytime, forever" and as a result, Java virtual machine was developed. One of the main problems is the execution speed of the program. Since Java is architecture neutral, it generates the byte code, which reassembles the machine code.
Interpreted and high performance
Java enables the creation of cross platform programs by compiling the code into the intermediate representation called java byte code. This code can be interpreted on any system that has a java virtual machine. Most of the cross platform solutions are run at the expense of performance.
Distributed
Java is designed for the distributed environment of the internet because it handles TCP/IP protocols. This allows objects on two different computers to execute procedures remotely. Java has recently revived these interfaces in a package called remote method invocation.
Dynamic
Java programs carry with them a broad amount of run time information that is used to verify and resolve access to objects at run time. Dynamic property of java adds an Applet environment.