code: public void ifExceptionThrow() throws Exception {
          if(nested == null || nested.isEmpty()) {
              return;
          }
          if (nested.size() == 1) {
              Throwable th = nested.get(0);
              if (th instanceof Error) {
                  throw (Error)th;
              }
              if (th instanceof Exception) {
                  throw (Exception)th;
              }
          }
          throw this;
      }
docs: Throw a MultiException.
  If this multi exception is empty then no action is taken. If it
  contains a single exception that is thrown, otherwise the this
  multi exception is thrown.
  
  @exception Exception the Error or Exception if nested is 1, or the
  MultiException itself if nested is more than 1.