javac ==> compilation
	Syntax: javac filename.java
java ==> execution
	syntax: java filename.java

Q: Is it possible to execute the java program without the compilation?
======================================================================
from Java11 ==> Standard
	no compilation is needed.
before java-11:
	java-8, java9, java10 etc.
		we must compile
		and then execute

=====================================================

Variables can be initialized in two ways:
	1) Compile time Initialization
		datatype name = value;
		datatype name;
		name = value;
	2) Run time Initialization
		we need a package "util"
		Scanner class (inbuilt) ==> import
		Syntax:
			import java.util.Scanner;
		We should create an object for the Scanner class to access the input methods to take the data for variable in run time. (main() method)
	Syntax:
		Scanner object-name = new Scanner(System.in);

IO Streams In Java:
===================
Input and Output Streams

Stream ==> byte code/group of data
have one pre-defined package 
	java.io
three streams:
	1) System.in: this is an inbuilt input stream
		use to read values while running of the program
	2) System.out:
		println()
		print()
		printf()
			we can write anything of the screen/console.
	3) System.err:
		println()
		print()
		printf()
			to write about error description

====================================
Taking of Integral Values in Run Time:
=====================================
==> to take integral values, we have four different built-in methods in Scanner class:
	1) nextByte() ==> we can use to read a byte value
		scanner-object.nextByte();
	2) nextShort()
	3) nextInt()
	4) nextLong()

import java.io.*;   // optional
import java.util.Scanner;   // mandatory
class IoOperations{
    public static void main(String s1[])
    {
        Scanner sco = new Scanner(System.in);
        byte b;
        short s;
        int i;
        long l;
        
        System.out.println("Enter all integral values:");
        b = sco.nextByte();
        s = sco.nextShort();
        i = sco.nextInt();
        l = sco.nextLong();
        
        System.out.println(b);
        System.out.println(s);
        System.out.println(i);
        System.out.println(l);
    }
}

Ravikumar
camel case: ravikumar
javaprogramminglanguage
camel case: javaProgrammingLanguage

================================================

Taking Floating-point data in run time:
=======================================
nextFloat()
nextDouble()

import java.io.*;   // optional
import java.util.Scanner;   // mandatory
class IoOperations{
    public static void main(String s1[])
    {
        Scanner sco = new Scanner(System.in);
        
        float f1,f2;
        double d1,d2;
        
        f1 = 1.223f;    // float
        d1 = 0.0012;    // double
        
        System.out.println("Enter a float value:");
        f2 = sco.nextFloat();
        
        System.out.println("Enter a double value:");
        d2 = sco.nextDouble();
        
        System.out.println(f1);
        System.out.println(f2);
        System.out.println(d1);
        System.out.println(d2);
    }
}

=============================================
Reading/taking of Boolean value in the run time:
===============================================
nextBoolean()

import java.io.*;   // optional
import java.util.Scanner;   // mandatory
class IoOperations{
    public static void main(String s1[])
    {
        Scanner sco = new Scanner(System.in);
        
        boolean b;
        
        System.out.println("Enter a boolean value:");
        b = sco.nextBoolean();
        
        System.out.println(b);
    }
}

=================================
Assignment:
===============
1) WAP to accept the character in the run time and print that character on the screen.