mplex, and best explained in the source itself. Essentially if
 either file doesnt exist, or the destfile has an out of date timestamp,
 then the return value is false.
 <p/>
 If we are signing ourself, the check <a href="../../../../../org/apache/tools/ant/taskdefs/SignJar.html#isSigned(java.io.File)"><code>isSigned(File)</code></a> is used to
 trigger the process.</div>
<dl><dt><span class="strong">Parameters:</span></dt><dd><code>jarFile</code> - the unsigned jar file</dd><dd><code>signedjarFile</code> -