code: @FFDCIgnore(PrivilegedActionException.class)
      private boolean isArchive(File f) {
          final File target = f;
          try {
              AccessController.doPrivileged(new PrivilegedExceptionAction<Void>() {
                  @Override
                  public Void run() throws IOException {
                      new ZipFile(target).close();
                      return null;
                  }
              });
          } catch (PrivilegedActionException e) {
              Exception innerException = e.getException();
              if (tc.isDebugEnabled()) {
                  Tr.debug(tc, "The following file can not be added to the classpath " + f + " due to error ", innerException);
              }
              return false;
          }
          return true;
      }
docs: Check that a file is an archive
  
  @param f