Java Program...

Link for Java Theory & Basic in more Detail....

// Random Number GenJava theory and Basicrater.....
class random_r{
    public static void main(String[] args) {

      
        // generate and print N numbers between 0 and 1,0 to 100...
        for (int i = 0; i < 12; i++)
    {       
            //indecimal   
            System.out.println(Math.random());
            //indecimal     with under the 100
            System.out.println((Math.random())*100);
            //with out the Decimal under the 100
            System.out.println((int) ((Math.random())*100));
        }
    }
}
}

//armstrong Program
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

class Armstrong
{
    public static void main(String args[])
    {
        int arm=153;
        int no=0;
        int n;       
        int temp=arm;

        while(arm>=0)
        {
            n=arm%10;
            no=no+(n*n*n);
            arm=arm/10;                       
        }
        System.out.println(no);
        if(temp==no)
            System.out.println(temp+" is an armstrong number");   
        else
            System.out.println(temp+" is not an armstrong number");
    }

//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//String Repalce Demo
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

 import java.io.*;
import java.util.*;

class StringReplace{
    public static void main(String args[])
    {
        Scanner sr=new Scanner(System.in);
      
        sr.nextLine();
        System.out.println(sr);      
    }
}



//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//Prime Number Demo
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
class PrimeNumber
{
    public static void main(String args[])
    {
        int flag=0;
       
        for(int i=2;i<=20;i++)
        {
            flag=0;
            for(int j=2;j<i;j++)
            {
                if(i%j==0)
                    flag=1;
            }
            if(flag==0)
                System.out.println(i+ " is prime number");
            else
                System.out.println("    "+i+" is not prime number");       
        }
    }
  }


//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// String Palindrome Demo
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
class StringPalindrome
{
    public static void main(String args[])
    {
       
        int length=args[0].length();
        boolean flag=false;
       
        for(int i=0;i<length;i++)
        {
            if(args[0][i]!=args[0][length-i])
            {
                flag=true;
            }
        }
        if(flag)
        {
            System.out.println("Entered String is not Palindrome");
        }
        else
            System.out.println("Entered String is Palindrome");   
            }
}


//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//  CommandLine Example Demo
 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
class CommandLineEx
{
    public static void main(String args[])
    {
        int n=Integer.parseInt(args[0]);
       
        for(int i=0;i<=n;i++)
        {
            for(int j=0;j<i;j++)
                System.out.print(" *");
            System.out.println();       
       }   
    }
}
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
//  RecursionFactorial Demo
 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
class RecursionFactorial1
{
    static int fact=0;
    public static void main(String []args)
    {
        int no;
        no=Integer.parseInt(args[0]);
        if(no<=0)
            return;
         no=--no;
        fact+=no * main(Integer.toString(no));       
        System.out.println(fact);   
    }
}
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
// Data Type Demo..........

 //++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

class DataTypes
{
    public static void main(String args[])
    {
        System.out.println(" Data Types");
        System.out.println("Class  DataType Size(Bytes)  MinValue \tMaxValue   Bits");
        //System.out.println("Integer int      "+(Integer.SIZE/4)+" "+Integer.MIN_VALUE+" "+Integer.MAX_VALUE+" "+Integer.SIZE);
        System.out.println("Integer     int    "+(Integer.SIZE/4)+"  \t"+Integer.MIN_VALUE+" "+Integer.MAX_VALUE+" "+Integer.SIZE);
        System.out.println("Short       short  "+(Short.SIZE/4)+  "  \t"+Short.MIN_VALUE+"   "+Short.MAX_VALUE+"   "+Short.SIZE);
        System.out.println("Long        long   "+(Long.SIZE/4)+  "   \t"+Long.MIN_VALUE+"    "+Long.MAX_VALUE+"   "+Long.SIZE);
        System.out.println("Float       float  "+(Float.SIZE/4)+  "  \t"+Float.MIN_VALUE+"   "+Float.MAX_VALUE+"   "+Float.SIZE);
        System.out.println("Double      double "+(Double.SIZE/4)+  " \t"+Double.MIN_VALUE+"  "+Double.MAX_VALUE+"   "+Double.SIZE);
        System.out.println("Character   char   "+(Character.SIZE/4)+"\t"+Character.MIN_VALUE+"   "+Character.MAX_VALUE+"   "+Character.SIZE); 
  }
}