Write a function that takes an (unsigned) integer as input, and returns the number of bits that are equal to one in the binary representation of that number.

Example: The binary representation of 1234 is 10011010010, so the function should return 5 in this case.

package poj;
public class BitCounting {public static int countBits(int n){String binaryStr = Integer.toBinaryString(n);int count = 0;for(int i=0; i<binaryStr.length(); ++i){if(binaryStr.charAt(i) == '1'){count++;}}return count;}
}

package poj;
import org.junit.Test;
import static org.junit.Assert.assertEquals;
import org.junit.runners.JUnit4;public class BitCountingTest {@Testpublic void testGame() {assertEquals(5, BitCounting.countBits(1234)); assertEquals(1, BitCounting.countBits(4)); assertEquals(3, BitCounting.countBits(7)); assertEquals(2, BitCounting.countBits(9)); assertEquals(2, BitCounting.countBits(10)); }
}