Deserialising different types to single field using Jackson

In general, I'd discourage the use of arbitrary types of data points. Having strong types gives plenty of benefits about which I can talk if you want. However, since you only talked about deserialization it might be that you are just reading such a JSON produced by someone else.

The solution is quite simply: use Object field.

public static class MyObject {    @JsonProperty("prop")    String prop;    @JsonProperty("value")    Object value;        // <- object}@Testpublic void testUnknownType() throws JsonProcessingException {    final ObjectMapper objectMapper = new ObjectMapper();    final MyObject object1 = objectMapper.readValue("{\n" +        "  \"prop\": \"myprop\",\n" +        "  \"value\": 15.7\n" +        "}", MyObject.class);    Assert.assertEquals(15.7d, object1.value);    final MyObject object2 = objectMapper.readValue("{\n" +        "  \"prop\": \"myprop1\",\n" +        "  \"value\": {\n" +        "    \"attr1\": \"value1\",\n" +        "    \"attr2\": 12.0\n" +        "  }\n" +        "}", MyObject.class);    Assert.assertTrue(object2.value instanceof Map);}

What you could is something like this:

@JsonDeserialize(using = ExampleDeserializer.class)public class Example{String prod;Object value; /*this field will takes multiple types*/}

and the ExampleDeserializer would be like this:

public class ExampleDeserializer extends StdDeserializer<Example> {    public ExampleDeserializer() {        super(Example.class);    }    public ExampleDeserializer(Class<?> vc) {        super(vc);    }@Override    public Example deserialize(JsonParser p, DeserializationContext ctx) throws IOException {        Example ex = new Example();        ObjectCodec mapper = p.getCodec();        if (mapper == null) mapper = new ObjectMapper();        JsonNode tree = mapper.readTree(p);        JsonNode internalNode;        if (tree.get("prod") != null) {          internalNode = tree.get("prod");          prop = internalNode.get("prod").asText();        }       if (tree.get("value") != null) {          internalNode = tree.get("value");          value = (Double) internalNode.get("value").asDouble() or asText()...;        }}

You'll have a slightly easier time of things if you have your different types as different names, so in JSON it should be:

{  prop: "my_map_prop",  mapvalue: {    "attr1": "value1",    "attr2": 12.0  }}

or

{  prop: "my_string_prop",  stringvalue: "string"}

If you do it like this you then have more tools at your disposal to enforce validity.