private void deleteMatching(final File dir, final Pattern pattern) throws IOException {
    Collection<File> files = listFiles(dir, new RegexFileFilter(pattern), DIRECTORY);
    for (File file : files) {
      Files.delete(file.toPath());
    }
  }
Verifies that a user deployed jar file is included as part of the backup.
geode-core/src/integrationTest/java/org/apache/geode/internal/cache/backup/IncrementalBackupIntegrationTest.java