final Thread.UncaughtExceptionHandler handler = (t, e) -> handlerCalled.set(true);

        indexUpdater.setUncaughtExceptionHandler(handler);
        assertSame(handler, indexUpdater.getUncaughtExceptionHandler());
    }

    // Test setDefaultUncaughtExceptionHandler
    @Test
    public void test_setDefaultUncaughtExceptionHandler() {