title: how can i get an hash/md5 from an object?
body: <p>I have a class like this</p>
  
  <pre><code>Class A{
  
    private String string1;
    private String string2;
    ..
    ..
  
    private String string19;
  
  }
  </code></pre>
  
  <p>Some of the strings may be empty.</p>
  
  <p>I want to get an hash/identifier (string or number) for the instances of this class.
  I can use hashCode but i don't know if i can get some collision, i have a lot of instances of this class (about 4-5 million).</p>
  
  <p>I need a fast way to get this hash.</p>
  
  <p>Thanks for the help.</p>