title: Java and Hash algorithm to compare files
body: <p>I have to fingerprint files to match doublets. What is recommended with Java in 2013? Should I also compare the file size, or is this a unnecessary check?</p>
  
  <p>The probability of false positive should be very close to 0</p>
  
  <p>EDIT: Lots of answers, thanks. What is the standard of backup software today? SHA-256? higher? I guess md5 is not suitable?</p>