title: Can I tell findbugs to ignore classes I am unable to add?
body: <p>Findbugs reports this:</p>
  
  <pre><code>findbugs:
   [findbugs] Executing findbugs from ant task
   [findbugs] Running FindBugs...
   [findbugs] The following classes needed for analysis were missing:
   [findbugs]   com.company.OptionalClass
   [findbugs] Warnings generated: 11
   [findbugs] Missing classes: 2
   [findbugs] Calculating exit code...
   [findbugs] Setting 'missing class' flag (2)
   [findbugs] Setting 'bugs found' flag (1)
   [findbugs] Exit code set to: 3
   [findbugs] Java Result: 3
   [findbugs] Classes needed for analysis were missing
   [findbugs] Output saved to findbugs.xml
  BUILD SUCCESSFUL
  </code></pre>
  
  <p>This OptionalClass is referenced from a third-party jar for which I do not have the source code, and for which I do not want a findbugs analysis. It refers to a class I do not have in my classpath, or anywhere else. This class is probably used in certain cases, when our third-party jar is configured in a certain way.</p>
  
  <p>Is there a way to tell findbugs to ignore this class?</p>
  
  <p>Note that it completes the analysis and produces a <code>findbugs.xml</code> report, so this is a minor issue.</p>