title: Two instances of same class running via main - what is their associated unique identifier of each thread of main?
body: <p>I am running the main method of a class twice, simultaneously via different executions and was looking at what would uniquely identify each one as it was running. It was simple to create something in myself:</p>
  
  <pre><code>String sid = UUID.randomUUID().toString(); 
  </code></pre>
  
  <p>...but <strong>is there anything inherent in each running execution</strong> - part of the executing class - that I could use as a unique identifier.</p>
  
  <p>We did a few approaches ourselves to see that we didn't know of something available we could use. We first wondered about using <code>Thread.currentThread().getName()</code> but both are <em>main</em>. I can't use <code>toString()</code> because there is no instance.    </p>
  
  <p><hr>
  <strong>Edit:</strong> <br>
  This class (GettingRollingClient) is what I'm running twice simultaneously, trying to differentiate between the two as they run... re-using a Java feature if I can: <br></p>
  
  <pre><code>java -cp "hazelcast-client-3.0.1.jar:hazelcast-3.0.1.jar:." GettingRollingClient
  </code></pre>