### Question:
TokenStorageServiceImpl implements TokenStorageService { String objectType(JsonNode jsonNode) { return Optional.ofNullable(jsonNode.get("objectType")) .map(JsonNode::asText) .orElse(null); }  @Override SCAResponseTO fromBytes(byte[] tokenBytes); @Override byte[] toBytes(SCAResponseTO response); @Override T fromBytes(byte[] tokenBytes, Class<T> klass); @Override String toBase64String(SCAResponseTO response);  }### Answer:
@Test void objectType() throws IOException { assertEquals("test1", tokenStorageService.objectType(mapper.readTree("{\"objectType\": \"test1\"}"))); assertNull(tokenStorageService.objectType(new TextNode(""))); assertNull(tokenStorageService.objectType(new TextNode("{}"))); assertNull(tokenStorageService.objectType(new TextNode(null))); }