SolrTestCaseJ4.beforeClass() / SolrTestCaseJ4.afterClass() are currently defined as private static void. This causes problems with Mockito, which requires all test framework methods (including @BeforeClass / @AfterClass) to be public.
The following test case will show this:
It will fail with java.lang.Exception: Method beforeClass() should be public
The very trivial fix is to change both methods to public static void