What is Java language?
Java is a programming language and platform-independent language first released by Sun Microsystems in 1995. The name Java originates from a sort of espresso bean, Java. Gosling came up with this name while having a coffee near his office.
Feature of Java :-
Applications:-
- Desktop Applications such as acrobat reader, media player, antivirus.
- Web Applications such as irctc.co.in, javatpoint.com,
- Enterprise Applications such as banking applications.
- Mobile
- Embedded System
- Smart Card
- Robotics
- Games
Difference betweeen C++ and JAVA
Data types of Java:-
In java has 8 primitive data types :
- Byte
- short
- int
- long
- double
- float
- boolean
- char
Basics of Java:-
- Object − Objects have states and behaviors. Example: A woman has states – color, name, height as well as behavior such as mood their sad, crying, eating. An object is an instance of a class.
- Class − A class can be defined as a blueprint that describes the state that the object of its type supports.
- Methods − A method is basically a behavior. A class can contain many methods. It is in methods where the logics are written, data is manipulated and all the actions are executed.
- Instance Variables − Each object has its unique set of instance variables.
Why java is platform independent language?
Java language is developed in such a way that it does not depend on any hardware and software. Due to the fact compiler compiles the code and then converts it into platform-independent byte code which can be run in multiple systems. The only condition is that JRE installs on it.
What is JDK,JRE and JVM?
JDK:- Java development kit.
It is a tool necessary to compile, document, and package Java programs. The JDK completely includes JRE.
JRE:- Java runtime environment.
It’s a runtime environment that implements JVM and provides all classes, libraries, and other files that uses at runtime.
JVM:-Java virtual machine.
It is an abstract machine.it provides a runtime environment in which java byte code can be executed.
Example:
public class MyFirstJavaProgram {
/* This is my first java program.
* This will print 'Hello World' as the output
*/
public static void main(String []args) {
System.out.println("Hello World"); // prints Hello World
}
}
Output
C:\> javac MyFirstJavaProgram.java C:\> java MyFirstJavaProgram Hello World
