JavaBasics.txt

Java: 
-high level programming language.
-Created by James Gosling in 1995
-Secure, fast and powerful 
-Support multi-paradiagram
-Huge community support
-used to develope mobile application,web-application,web servers,games,desktop application,database connection.
-Runs on more than 3illion Devices.

Java Program Execution:
-Source code---(compiler)--->byte Code---(JVM)--->Machine Code

Java Platform Independent(WORA):
-bytecode(.class file) can be executed any platform.

Access Specifier:
-Defines the scope or availability of the classes, interfaces, variable, etc.

-Public: access from anywhere in the program.
-Private: access from the class where they are defined.
-Protected: access from the class, package, subclass and from within the class.
-Default: access available from all classess that belong the same package.

Method:
-Block of code also called as function.
-take input as parameter.
-Must be declared within  a class.
-In-built method and User-define method.

Java main() Method:
-Entry point of a java program.

(String[] args):
-String[]: used to declare a simple String array.
-args: name of the String array.
-args: store the command line arguments

Static method:
-can be called without creating an object of the class.
-Belongs to the class.
-No requirement of any object state.
-access directly by specifying its name.

Method Overloading:
-multiple method have same name but different Parameter.

Constructor:
-Special method used to initialize an object.
-do not have a return type.
-must have the same name as that of the class.

Types:
-No argument constructor
-Parameterized constructor
-Default constructor


Inheritance:
-process where class acquires the attribute and  methods of another class.
-code reusability.
-use 'extend' keyword for implementation

Final variable:
-used to avoid overiding and modifying.

Package:
-group related classes.
-Collection of related classes.
-Avoid name conflicts between classes and it allow to write better maintainable code.

Type:
-Built-in(java.lang,.io,.applet,.awt..util) and User-defined


Abstract class:
-restricted class where we cannot create object of the class.
-to access it most br inherited to a subclass.