title: How to convert a byte array to its numeric value (Java)?
body: <p>I have an 8 byte array and I want to convert it to its corresponding numeric value.</p>
  
  <p>e.g.</p>
  
  <pre><code>byte[] by = new byte[8];  // the byte array is stored in 'by'
  
  // CONVERSION OPERATION
  // return the numeric value
  </code></pre>
  
  <p>I want a method that will perform the above conversion operation.</p>