Incorrect error description (NullPointerException) when using a non-uri value in the id field

[antonovdmitriy]

Description

Insufficiently clear description of the error when using a non-uri value in the id field at the root of the schema element. It would be better to show a competent message about incorrect format

Repeating

{
  "id": "JustSomeStringValue",
  "$schema": "http://json-schema.org/draft-04/schema#",
  "type": "object",
  "properties": {
    "field1":{
      "type": "string"
    }
  }
}

    JsonSchemaFactory factory = JsonSchemaFactory.getInstance(SpecVersion.VersionFlag.V4);
    InputStream is = Thread.currentThread().getContextClassLoader()
            .getResourceAsStream("test.json");
    JsonSchema node =  factory.getSchema(is);```

output

[stevehu]

@AntonovDmitriy Thanks for raising it. I am wondering if you could submit a PR to get it fixed.

[ottomata]

Also, $id is not required to be a fully qualified URL. At the Wikimedia Foundation we use relative path URIs for $ids and provide base URIs when resolving them.

I just tried to use this library but realized I can't because our relative path $ids (e.g. "/entity/event/1.0.0") cause a similar exception. I think more recent versions have this NPE caught. The exception I get is:

com.networknt.schema.JsonSchemaException: /test/event/1.0.0: null is an invalid segment for URI {2}

[hscissors]

Not to necrobump this, but I'm running into this exact issue. Our schema still loads, but it's still throwing the error in logs. Any work around?