code: public static Long nextLong() {
          long randomLong = RANDOM.nextLong();
          if (randomLong < 0) {
              randomLong = randomLong + 1;
              randomLong = Math.abs(randomLong);
          }
          return randomLong;
      }
docs: <p> Returns the next pseudorandom, uniformly distributed long value from the Math.random() sequence. </p>
  NB! All values are greater than or equal to zero.
  
  @return The random long.