Checks if a String is empty (""), null and whitespace only in Java

/*from w  ww.j a  v a2  s  . co m*/
public class Main {
  public static boolean isBlank(String str) {
      int strLen;
      if (str == null || (strLen = str.length()) == 0) {
          return true;
      }
      for (int i = 0; i < strLen; i++) {
          if ((Character.isWhitespace(str.charAt(i)) == false)) {
              return false;
          }
      }
      return true;
  }
  public static void main(String[] argv){
     System.out.println(isBlank("java2s.com"));
  }
}