  <div class="jd-descr">
    A small toolkit of classes that support lock-free thread-safe
 programming on single variables.  In essence, the classes in this
 package extend the notion of <code>volatile</code> values, fields, and
 array elements to those that also provide an atomic conditional update
 operation of the form:

  <pre> <code>boolean compareAndSet(expectedValue, updateValue);</code></pre>

 <p>This method (which varies in argument types across different
 classes) atomically sets a variable to t