<p>Perform <code>numTests</code> idle object eviction tests, evicting
examined objects that meet the criteria for eviction. If
<code>testWhileIdle</code> is true, examined objects are validated
when visited (and removed if invalid); otherwise only objects that
have been idle for more than <code>minEvicableIdleTimeMillis</code>
are removed.</p>
@throws Exception when there is a problem evicting idle objects.
<p>Perform <code>numTests</code> idle object eviction tests, evicting examined objects that meet the criteria for eviction. If <code>testWhileIdle</code> is true, examined objects are validated when visited (and removed if invalid); otherwise only objects that have been idle for more than <code>minEvicableIdleTimeMillis</code> are removed.</p>
@throws Exception when there is a problem evicting idle objects.