Object oriented language

• Object

  An object is an unique entity. It is the component in a program that knows how to perform certain tasks and how to interact with elements.
• Class

  A class is a group of similiar objects having similar characteristics and behaviour.
• Encapsulation

  The wrapping up of data and associated functions into a single unit.
• Functions of encapsulation

  1. Code and data are secure from unauthorised access.

  2. User does not know internal mechanisms

  3. Improves the maintainability and flexibility of program
• Abstraction


  Abstraction shows only necessary information and hides the background details.
• Polymorphism


  It implies that a function should be used multiple times in a program. It allows the different internal interface of the object without any change in the external interface.
• Inheritance


  Inheritance basically means acquiring features. A class can be extended by using inheritance. Inheritance is the feature that helps build new classes from previously existing classes.
• History and Development of java

  Java was developed by James gosling. at sun microsystems Inc in 1991 and was later acquired by oracle corporation.
• Java

  Java is a simple, object oriented, distributed, interpreted, secure, robust, architecture neutral, portable, high performance, multi threaded and dynamic language.
• Platform Independent language

  The compiler turns source code (.java file) to byte code (.class file) . this byte code can run on any platform. Each Operating system has a JVM however the output produces after execution of byte code remains same.
• Object Oriented language

  It is an object oriented language. Each object represents an instance of a class.
• Simple


  Java is simple because its syntax is clear, easy and clean. Many infrequently used features have been removed i.e. operator overloading, explicit pointers etc.
• Robust Language

  Robust is reliable. Java is developed in a way that it puts a lot of emphasis on early checking for errors due to this java is able to detect errors that are not easily detected. Main features are Garbage collection, exceptional handling, memory allocation.
• Secure


  The data of a class cannot be accessed unless a native function of the class provides authorization. (abstraction)
• Distributed Language

  
  

  Using the Java programming language, you can create distributed applications. Remote Method Invocation (RMI) and Enterprise Java Beans (EJB) are used for creating distributed applications in Java. In simple words, Java programs can be distributed on more than one system that are connected to each other using the internet connection. Objects on one Java Virtual Machine (JVM) can execute procedures on a remote JVM.
• Multithreading


  Java supports multithreading. Multithreading is a Java feature that allows concurrent execution of two or more parts of a program for maximum utilisation of the CPU.
• Portable


  Java code that is written on one machine can run on another machine. Th platform independent byte code can be carried to any platform for execution that makes Java co portable.
• Standalone System (Java Applications)


  The Java programming language is widely accepted as a development technology for standalone (desktop applications) development. Such programs or applications destined to run on desktop applications, like word processors or spreadsheets.
• Internet Applets (Java Applets)


  Internet Applets are small programs that need a web browser and are run on the machine in a secure manner by Java capable browsers. Applets are designed to be transferred to web browsers. This is the reason why an applet has a built-in graphic window.
• Compiler

  A compiler is a program that translates code written in a high-level language into machine code, in one go.

  ◆ A compiler is more intelligent than an assembler. It checks all kinds of limits, ranges, errors, etc.

  It occupies a larger part of memory.

  ◆ During execution, the object code is loaded into the computer's memory. The computer then directly executes the object code. That is why, the execution of a compiled program is fast.
• Interpreter


  An interpreter is a program that translates the source code instructions into machine code, line-by-line.

  + It translates only one statement of the program at a time.

  + During the program execution, the interpreter runs in a loop reading the next statement from the source code and translates it into the necessary machine code. The execution of an interpreted program is slow.
• normal compilation

  In normal compilation, the source code is directly converted to machine code.
• Java compilation

  In Java compilation, the source code is first converted to an intermediate code i.e the Java Byte Code, which in turn is converted to the machine code.
• Java Development Kit (JDK)


  The Java Development Kit (JDK) is a product of Sun Microsystems used to develop Java software and is an extended subset of a Java Software Development Kit (SDK). JDK consists of the API classes, a Java compiler, and the Java Virtual Machine interpreter.