Java program codes: reverse string in java

public class ReverseStringTest {
  public static void main(String[] args) {
    String str = "What's going on?";
    System.out.println(ReverseString.reverseIt(str));
  }
}

class ReverseString {
  public static String reverseIt(String source) {
    int i, len = source.length();
    StringBuffer dest = new StringBuffer(len);

    for (i = (len - 1); i >= 0; i--)
      dest.append(source.charAt(i));
    return dest.toString();
  }
}