Power of Two
by Isai Damier, Android Engineer @ Google

/***************************************************************************
 * Author: Isai Damier
 * Title: isPowerOfTwo
 * Project: geekviewpoint
 * Package: algorithms
 *
 * Statement:
 *   Indicate whether the given integer n is a power of two.
 *
 * Sample Input:  16
 * Sample Output: true
 *
 * Technical Details:
 *   A number that is a power of two only has one set bit: 0 = 0; 2 = 10;
 *   4 = 100; 8 = 1000; 16 = 10000; etc. Therefore checking whether a number
 *   is a power of two is as simple as clearing the lowest set bit and then
 *   checking that the result is equal to zero. (ref to clearLowestBit above)
 *
 ***************************************************************************/ 
 public boolean isPowerOfTwo(int n) {
  return 0 == (n & (n - 1));
}

import org.junit.Test;
import static org.junit.Assert.*;

public class BitwiseTest {

 /**
   * Test of isPowerOfTwo method, of class Bitwise.
   */
  @Test
  public void testIsPowerOfTwo() {
    System.out.println(""isPowerOfTwo"");
    Bitwise bits = new Bitwise();
    for (int i = 1; i < 31; i++) {
      assertTrue(bits.isPowerOfTwo((int) Math.pow(2, i)));
    }
  }
}