@Test public void testSaveTwoRootObjectsWithNoType() { JsonNode expected = mapper .createArrayNode() .add(mapper.createObjectNode().put("userId", "1").put("name", "Paul")) .add( mapper .createObjectNode() .put("userId", "2") .put("name", "Anna") .put("sex", "FEMALE")); User u1 = ModelFactory.eINSTANCE.createUser(); u1.setUserId("1"); u1.setName("Paul"); User u2 = ModelFactory.eINSTANCE.createUser(); u2.setUserId("2"); u2.setName("Anna"); u2.setSex(Sex.FEMALE); Resource resource = new JsonResource(URI.createURI("test"), mapper); resource.getContents().add(u1); resource.getContents().add(u2); JsonNode result = mapper.valueToTree(resource); assertEquals(expected, result); }