on requires
 good liveliness for <code>get</code> and <code>put</code>. Various tradeoffs
 have been made with this in mind.
 <p>
 <strong>Usage:</strong> typical use case is as a drop-in replacement
 for the <code>Hashtable</code> used in <code>LogFactory</code> for J2EE environments
 running 1.3+ JVMs. Use of this class <i>in most cases</i> (see below) will
 allow classloaders to be collected by the garbage collector without the need
 to call <a href="../../../../../org/apache/commons/logging/LogFactory.h