code: private void loadImplementationsInJar(final Test test, final String parent, final File jarFile) {
          @SuppressWarnings("resource")
          JarInputStream jarStream = null;
          try {
              jarStream = new JarInputStream(new FileInputStream(jarFile));
              loadImplementationsInJar(test, parent, jarFile.getPath(), jarStream);
          } catch (final FileNotFoundException ex) {
              LOGGER.error("Could not search jar file '" + jarFile + "' for classes matching criteria: " + test
                      + " file not found", ex);
          } catch (final IOException ioe) {
              LOGGER.error("Could not search jar file '" + jarFile + "' for classes matching criteria: " + test
                      + " due to an IOException", ioe);
          } finally {
              close(jarStream, jarFile);
          }
      }
docs: Finds matching classes within a jar files that contains a folder structure matching the package structure. If the
  File is not a JarFile or does not exist a warning will be logged, but no error will be raised.
  
  @param test
  a Test used to filter the classes that are discovered
  @param parent
  the parent package under which classes must be in order to be considered
  @param jarFile
  the jar file to be examined for classes