code: @SuppressWarnings("unchecked")
  	public static <T> TypeInformation<T> convert(String jsonSchema) {
  		Preconditions.checkNotNull(jsonSchema, "JSON schema");
  		final ObjectMapper mapper = new ObjectMapper();
  		mapper.getFactory()
  			.enable(JsonParser.Feature.ALLOW_COMMENTS)
  			.enable(JsonParser.Feature.ALLOW_UNQUOTED_FIELD_NAMES)
  			.enable(JsonParser.Feature.ALLOW_SINGLE_QUOTES);
  		final JsonNode node;
  		try {
  			node = mapper.readTree(jsonSchema);
  		} catch (IOException e) {
  			throw new IllegalArgumentException(
  				"Invalid JSON schema.", e);
  		}
  		return (TypeInformation<T>) convertType("<root>", node, node);
  	}
docs: Converts a JSON schema into Flink's type information. Throws an exception if the schema
  cannot converted because of loss of precision or too flexible schema.
  
  <p>The converter can resolve simple schema references to solve those cases where entities
  are defined at the beginning and then used throughout a document.