When the OS runs out of file handles a NPE is thrown in FileURLListener:

2005-06-15 16:33:42,951 ERROR [org.jboss.deployment.scanner.AbstractDeploymentScanner$ScannerThread] Scanning failed; continuing
java.lang.NullPointerException
at org.jboss.net.protocol.file.FileURLLister.listFiles(FileURLLister.java:71)
at org.jboss.net.protocol.file.FileURLLister.listMembers(FileURLLister.java:40)
at org.jboss.deployment.scanner.URLDeploymentScanner.scan(URLDeploymentScanner.java:379)
at org.jboss.deployment.scanner.AbstractDeploymentScanner$ScannerThread.doScan(AbstractDeploymentScanner.java:204)
at org.jboss.deployment.scanner.AbstractDeploymentScanner$ScannerThread.loop(AbstractDeploymentScanner.java:215)
at org.jboss.deployment.scanner.AbstractDeploymentScanner$ScannerThread.run(AbstractDeploymentScanner.java:194)

The attached patch fixes the problem.