mapper.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
// Ok, first test JSON Object containing buffer:
TokenBuffer buf = new TokenBuffer(mapper);
buf.writeStartObject();
buf.writeNumberField("num", 42);
buf.writeEndObject();
String json = mapper.writeValueAsString(new ObjectHolder(buf));
ObjectHolder holder = mapper.readValue(json, ObjectHolder.class);
assertNotNull(holder.value);
assertSame(TokenBuffer.class, holder.value.getClass());