code: protected Statement withBeforeClasses(Statement statement) {
          List<FrameworkMethod> befores = testClass
                  .getAnnotatedMethods(BeforeClass.class);
          return befores.isEmpty() ? statement :
                  new RunBefores(statement, befores, null);
      }
docs: Returns a {@link Statement}: run all non-overridden {@code @BeforeClass} methods on this class
  and superclasses before executing {@code statement}; if any throws an
  Exception, stop execution and pass the exception on.