Java Code Example: diamond pattern

public class DiamondPattern {
  public static void main(String[] args) {
    int i, j, rows = 8;

    // upper pyramid
    for (i = 0; i <= rows; i++) {
      for (j = 1; j <= rows - i; j++) {
        System.out.print(' ');
      }
      for (j = 1; j <= 2 * i - 1; j++) {
        System.out.print('*');
      }
      System.out.print("\n");
    }

    // lower pyramid
    for (i = rows - 1; i >= 1; i--) {
      for (j = 1; j <= rows - i; j++) {
        System.out.print(' ');
      }
      for (j = 1; j <= 2 * i - 1; j++) {
        System.out.print('*');
      }
      System.out.print("\n");
    }
  }
}

Output

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