@Test public void testExists() { List<TestEntity> values = Arrays.asList(1, 2) .stream() .map( v -> { TestEntity t = new TestEntity(); t.setStringProperty(String.format("Hello %s time(s)", v)); return t; }) .collect(Collectors.toList()); repository.save(values); assertTrue(repository.exists(values.get(1).getId())); assertFalse(repository.exists("3")); }