What is java

Java is a Object Oriented Programming Language. Java programming language is widely used in many areas like web development and gaming applications. Java is a simple, easy to use, platform independent programming language which is used for many purposes.

 The features of Java Programming language are:

  • Abstraction : is a process of hiding information and showing the essential information. 
  • Encapsulation: storing data members and methods in a single unit called class
  • Inheritance: Inheritance simply refer to code reusability. Where a class inherits properties from the class or interface.
  • Platform independent programming language
  • Multithreaded: Java programming language is a multithreaded programming language.


 Java comes in various editions to cater to various types of application development needs.

Two key editions of Java are:

  1. Java Standard Edition
  2. Java Enterprise Edition

 

To learn Java programming fundamentals, we need Java SE.

Java SE (Standard Edition)

This edition consists of libraries for building core Java applications.

Java EE (Enterprise Edition)

This edition consists of libraries for building distributed Java applications. These libraries depend on Java SE libraries

Java is a high-level, general-purpose programming language developed by a small team, headed by James Gosling and Patrick Naughton at Sun Microsystems in 1991. It is currently owned by Oracle Corporation.

It was designed to be small, simple, and portable across platforms and operating systems.

It was initially developed for consumer devices. Later it has become a popular platform to develop enterprise applications.

You must have observed, a program has several components and blocks. It has words as well. Some of these words are reserved and have a special meaning in Java, e.g., class, public, void, for, int, static. These words are known as keywords. Currently, Java has 50 keywords.

keywords are the words which we cannot use to name our variable or method  and they are reserved in any programming language. There are 50 keyword in java programming language and they are case sensitive.

Keywords in java:

Keywords are the words in java we cannot use like an identifier, each keyword has a specific use and we must know which keyword should be used. For example: 'String' is a keyword in java and it is data type also and 'String' is used to declare, define a variable and methods.
Keywords are case sensitive. for example: the word "int" and "Int" are different in java programming language.
List of Keywords in java:
abstract             assert            boolean             break                byte            case           catch          char  class                  const            continue            default              do               double       else            enum
extends              final             finally               float                  for               goto           if                int
implements        import         instanceof          interface           long            native        package      private
protected            protected     public                 public              return          short          static          strictfp
super


Identifiers in Java:

As in other programming language there are identifiers to identify the different methods and vaiables. The variable names and method names are called as identifiers.

User-defined words to identify different components of a program, e.g., Account, main known as Identifiers. These words are known as Identifiers. Identifiers are names used for identifying components of a program like classes, methods, interfaces, enums, and variables. After defining once, we can use them again to identify corresponding components in the program.

Rules for identifier:

  • Case-sensitive
  • Should not start with a number
  • Can start with a letter, $ or _
  • Should not have spaces
  • Should not be a Java keyword or literal
  • No restriction on the length

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