String[] inputs2 = { "a", "b" };
        String[] inputs3 = { "c", "d" };

        CharMappingItem item1 = new CharMappingItem(1L, inputs1, "output");
        CharMappingItem item2 = new CharMappingItem(2L, inputs2, "output");
        CharMappingItem item3 = new CharMappingItem(3L, inputs3, "output");
        CharMappingItem item4 = new CharMappingItem(4L, inputs1, "different");

        // Same inputs and output should have same hash code

        CharMappingItem item1 = result1.get();
        assertEquals(1L, item1.getId());
        assertArrayEquals(new String[] { "a", "b" }, item1.getInputs());
        assertEquals("c", item1.getOutput());

        OptionalEntity<CharMappingItem> result2 = charMappingFile.get(2L);
        assertTrue(result2.isPresent());
        CharMappingItem item2 = result2.get();
        assertEquals(2L, item2.getId());

    //                                                                        ============

    private static OptionalEntity<CharMappingItem> getEntity(final CreateForm form) {
        switch (form.crudMode) {
        case CrudMode.CREATE:
            final CharMappingItem entity = new CharMappingItem(0, StringUtil.EMPTY_STRINGS, StringUtil.EMPTY);
            return OptionalEntity.of(entity);
        case CrudMode.EDIT: