Pattern Program

/*
 *

Enter an even number : 4

 *  *  *  *
 *        *
 *        *
 *  *  *  *

 
 */
/*
 * No negative inputs please
 */
/**
 * A quote: there are more than one ways to do it
 */
package javaapplication2;

import java.util.Scanner;

/**
 *
 * @author Umang
 */
public class Main
{
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args)
    {

        // loop variables
        int j = 0, k = 0;

        Scanner s = new Scanner(System.in);

        System.out.print("Enter a number : ");

        int n = s.nextInt();


        System.out.print("\n");

        for (j = 0; j < n; j++)
        {

            for (k = 0; k < n; k++)
            {

                if (k == 0 || k == n - 1 || j == 0 || j == n - 1)
                {

                    System.out.print(" * ");
                }
                else
                {
                    System.out.print("   ");
                }
            }

            System.out.print("\n");
        }
    }
}

Pattern Program

/**
 * user inputs a number greater than 2
 */
/**
run:
Enter an even number : 4

          *
       *     *
    *           *
 *                 *
    *           *
       *     *
          *


 */

/*
 * No negative inputs please
 */
/**
 * A quote: there are more than one ways to do it
 */
package javaapplication2;

import java.util.Scanner;

/**
 *
 * @author Umang
 */
public class Main
{
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args)
    {

        boolean b = false;

        // to print inner stars
        int n1 = 0;

        int n2 = 0;

        // loop variables
        int j = 0, k = 0;

        Scanner s = new Scanner(System.in);

        System.out.print("Enter an even number : ");

        int n = s.nextInt();

        n1 = n2 = n / 2 + 1;

        
        System.out.print("\n");

        for (j = 0; j <= n +2 ; j++)
        {

            for (k = 0; k < n * 2; k++)
            {

                if (k == n1 || k == n2)
                {

                    System.out.print( " * " );
                }
                else
                {

                    System.out.print("   ");
                }
            }
            if(j-1==n/2)
            {

                b = true;
            }
            if (b == false)
            {

                n1--;
                n2++;
            }
            else
            {
                n1++;

                n2--;
            }
            System.out.print("\n");
        }
    }
}

Pattern Program

/********************************************************************

 *i wrote this program when one great person was sitting with me :-)* 

 ********************************************************************/



/*

Output:

Enter an Odd number : 5



 * * * * *

 *   *   *

 * *   * *

 *   *   *

 * * * * *



 */

// you can also do the same program using 3 loops



/*

 * No negative inputs please

 */

/**

 * A quote: there are more than one ways to do it

 */

package javaapplication2;



import java.util.Scanner;



/**

 *

 * @author Umang

 */

public class Main

{

    /**

     * @param args the command line arguments

     */

    public static void main(String[] args)

    {

        boolean b = false;



        // to print inner stars

        int n1 = 0;

        int n2 = 0;

        // n1 and n2 indicate in which column the inner stars should be

        // placed.

        // in each iteration (of outer loop), the value of

        // these two variables are changed



        // loop variables

        int j = 0, k = 0;



        Scanner s = new Scanner(System.in);



        System.out.print("Enter an Odd number : ");

        int n = s.nextInt();



        n1 = n2 = n / 2;



        System.out.print("\n");



        for (j = 0; j < n; j++)

        {

            for (k = 0; k < n; k++)

            {

                // if it is first or last line then print only *

                // no spaces in first and last line

                if (j == 0 || j == n - 1)

                {

                    System.out.print(" * ");

                }

                else

                {

                    // we come here if it is not first or last line



                    // n1 and n2 are the variables that hold informatin regarding where

                    // we want to print inner *s



                    // print * if it is the first or last column

                    // or the column value = n1 or n2

                    if (k == n1 || k == n2 || k == 0 || k == n - 1)

                    {

                        System.out.print(" * ");

                    }

                    else

                    {

                        // print blank space

                        System.out.print("   ");

                    }

                }

            }

            // prnit new line


            System.out.println();



            // now change the place of inner *s

           

            // this if changes the increment decrement pattern

            if (j == (n / 2))

            {

                // if j == n / 2 then we need to change the pattern

                // in which the numbers are incrementd



                // b is a flag variable

                b = true;

            }

            if (j != 0 && j != n - 1)

            {

                if (b == false)

                {

                    // we come here if we are in first upper part of pattern

                    n1--;

                    n2++;

                }

                else

                {

                    // we come here if we are in lower part of pattern


                    n1++;

                    n2--;

                }

            }

        }

        System.out.print("\n");

    }

}