title: Apache poi excel color cell issue
body: <p>I am using apache poi to write excel data.</p>
  
  <pre><code>String colour = "A2C465";
  byte[] ret = new byte[3];
  for(int i=0; i&lt;3; i++){
      ret[i] = (byte)hexToInt(colour.charAt(i * 2), colour.charAt(i*2+1));
  }
  
  public int hexToInt(char a, char b){
          int x = a &lt; 65 ? a-48 : a-55;
          int y = b &lt; 65 ? b-48 : b-55;
          return x*16+y;
      }
  </code></pre>
  
  <p>After the loop iteration I am getting ret = {-94,-60,101}.But the actual RGB code is {162,196,101}(since converting from int to byte).Because of this the color coming as different one in excel sheet.Can you help me in this?</p>