code: private static void addCauseToBacktrace(final Throwable cause, final List<String> bTrace) {
          if (cause.getMessage() == null) {
              bTrace.add(BT_CAUSED_BY_PREFIX + cause.getClass().getName());
          } else {
              bTrace.add(BT_CAUSED_BY_PREFIX + cause.getClass().getName() + ": " + cause.getMessage());
          }
          for (final StackTraceElement ste : cause.getStackTrace()) {
              bTrace.add(BT_PREFIX + ste.toString());
          }
          if (cause.getCause() != null) {
              addCauseToBacktrace(cause.getCause(), bTrace);
          }
      }
docs: Add a cause to the backtrace.
  
  @param cause
  the cause
  @param bTrace
  the backtrace list