title: Java profiling: java.lang.Object.hashCode takes half of the CPU time but never explictly called
body: <p>I have been benchmarked my multihreaded program using <code>-agentlib:hprof=cpu=samples</code>
  and was surprised to find the following line in the results:</p>
  
  <pre><code>rank   self  accum   count trace method
     1 52.88% 52.88%    8486 300050 java.lang.Object.hashCode
  </code></pre>
  
  <p>I never explicitly call hashCode() in my program.
  What can be the reason for this? How can I understand the source for this time "waste" and whether it is normal or not?</p>
  
  <p>Thanks,
  David</p>