title: How to read negative byte values in Java less than -128
body: <p>I'm reading data from another system using the serial port.  I'm reading packets of 133 bytes.  The second byte is the packet number and the third byte is the negative value of the packet number.</p>
  
  <p>The problem is that the type <code>byte</code> has a range of -128 to 127.  When I attempt to read -129 (outside the range of byte) it will give the value as 127.   </p>
  
  <p>What should I do so I can get -129?</p>