<p> The code synchronizes on a boxed primitive constant, such as an Integer.
<pre>
private static Integer count = 0;
...
  synchronized(count) { 
     count++;
     }
...
</pre>
</p>
<p>Since Integer objects can be cached and shared,
this code could be synchronizing on the same object as other, unrelated code, leading to unresponsiveness
and possible deadlock</p>