### Question:
TransactionHookManager { public static void clear() { LOCAL_HOOKS.remove(); } private  TransactionHookManager(); static List<TransactionHook> getHooks(); static void registerHook(TransactionHook transactionHook); static void clear();  }### Answer:
@Test public void testClear() { assertThat(TransactionHookManager.getHooks()).isEmpty(); TransactionHookManager.registerHook(new TransactionHookAdapter()); assertThat(TransactionHookManager.getHooks()).isNotEmpty(); TransactionHookManager.clear(); assertThat(TransactionHookManager.getHooks()).isEmpty(); }