ACM - UVA 100 - The 3n + 1 problem ( java )

The problem:100 - The 3n + 1 problem
The solution: Java
Hints: http://www.algorithmist.com/index.php/UVa_100
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
 public static void main(String[] args) throws IOException {
  Q100 q100 = new Q100();
  final BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
  String line;
  while ((line = reader.readLine()) != null) {
   String REGEX_WHITESPACE = "\\s+";
   String cleanLine = line.trim().replaceAll(REGEX_WHITESPACE, " ");
   String[] tokens = cleanLine.split(REGEX_WHITESPACE);
   if (tokens.length == 2) {
    long a = new Long(tokens[0]).longValue();
    long b = new Long(tokens[1]).longValue();
    System.out.println(cleanLine + " " + q100.countMaxIterationBetweenTwoNumbers(a, b));
   }
  }
 }

 public static class Q100 {
  private final long MAX_CACHE_SIZE = 65536;
  private final long[] cache = new long[(int) MAX_CACHE_SIZE];
  public long countIteration(long originalNumber) {
   long n = originalNumber;
   long count = 1;
   while (n > 1) {
    if (((n - 1) >> 1) == (n >> 1)) {
     long newNumber = (3 * n) + 1;
     if (newNumber < n) {
      throw new RuntimeException("overflow :" + originalNumber);
     } else {
      n = newNumber;
     }
    } else {
     n = n >> 1;
    }
    if (n < MAX_CACHE_SIZE && cache[(int) n] != 0) {
     return count + cache[(int) n];
    }
    count++;
   }
   return count;
  }

  public long countMaxIterationBetweenTwoNumbers(long a, long b) {
   final long big;
   final long small;
   if (a > b) {
    big = a;
    small = b;
   } else {
    small = a;
    big = b;
   }
   long winner = -1;
   for (long i = small; i <= big; i++) {
    long count = countIteration(i);
    if (i < MAX_CACHE_SIZE) {
     cache[(int) i] = count;
    }
    if (count > winner) {
     winner = count;
    }
   }
   return winner;
  }
 }
}