stanfordnlp/CoreNLP · error · NullPointerException

Image does not have height

Error message

Image does not have height

What it means

SceneGraphImage.readFromJSON reads image metadata from a JSON object. It calls obj.getInt("height") and then checks the result; since JsonObject.getInt never returns null, the guard is effectively a schema assertion — but when the "height" key is absent/invalid the resulting failure surfaces as a NullPointerException with message "Image does not have height" at src/edu/stanford/nlp/scenegraph/image/SceneGraphImage.java:89. It means the input JSON is missing the required height field.

Solutions

1. Add the required "height" integer field to the JSON record.
2. Re-download the complete image metadata from the dataset source.
3. Pre-validate the JSON with containsKey/isNull before calling readFromJSON and skip or repair bad records.
4. Supply a default height from a separate metadata source if only dimensions are missing.

Example fix

// before
SceneGraphImage img = SceneGraphImage.readFromJSON(obj); // NPE, no height
// after
if (!obj.containsKey("height") || obj.isNull("height")) {
  obj.put("height", imageHeightLookup(obj.getInt("id")));
}
SceneGraphImage img = SceneGraphImage.readFromJSON(obj);

if (!obj.containsKey("height") || obj.isNull("height") || !obj.containsKey("width") || obj.isNull("width")) {
  throw new IllegalArgumentException("Image record missing dimensions: " + obj.getInt("id"));
}

boolean hasDimensions(JsonObject o) {
  return o.containsKey("height") && !o.isNull("height") && o.containsKey("width") && !o.isNull("width");
}

try {
  return SceneGraphImage.readFromJSON(obj);
} catch (RuntimeException e) {
  log.warn("Skipping image without height: " + obj.getInt("id"));
  return null;
}

When it happens

Trigger: Calling readFromJSON (directly or via SceneGraphImage.readFromFile/img) on a JSON object without an integer "height" key, or with "height": null.

Common situations: Scene-graph dataset files trimmed to only region/relationship data; custom JSON built by scripts that omit metadata fields; partial downloads of Visual Genome image metadata.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• Image does not have width
• We need at least 2 extractors for ExtractorMerger to make se
• Too many columns: <columnI>/<numColumns> (offset: <offset>)
• Too few columns: <columnI>/<numColumns> (offset: <offset>)
• Sentence.toSentence: lengths differ

AI-assisted analysis of stanfordnlp/CoreNLP@1b7edd19c4 (2026-09-10). Data as JSON: /api/errors/15028f9e6c2b0b3d. Report an issue: GitHub.

Appendix: source

Thrown at src/edu/stanford/nlp/scenegraph/image/SceneGraphImage.java:89

      for (JsonObject object: objects.getValuesAs(JsonObject.class)) {
        img.objects.add(SceneGraphImageObject.fromJSONObject(img, object));
      }

      JsonArray attributes = obj.getJsonArray("attributes");
      for (JsonObject object: attributes.getValuesAs(JsonObject.class)) {
        img.addAttribute(SceneGraphImageAttribute.fromJSONObject(img, object));
      }

      JsonArray relationships = obj.getJsonArray("relationships");
      for (JsonObject relation: relationships.getValuesAs(JsonObject.class)) {
        img.addRelationship(SceneGraphImageRelationship.fromJSONObject(img, relation));
      }

      img.id = obj.getInt("id");
      Number height = obj.getInt("height");
      Number width = obj.getInt("width");
      if (height == null) {
        throw new NullPointerException("Image does not have height");
      }
      if (width == null) {
        throw new NullPointerException("Image does not have width");
      }
      img.height = height.intValue();
      img.width = width.intValue();

      img.url = obj.getString("url");

      return img;
    } catch (RuntimeException e) {
      throw new RuntimeException("Couldn't parse \n" + json, e);
    }
  }

  @SuppressWarnings("unchecked")
  public String toJSON() {
    JsonObjectBuilder json = Json.createObjectBuilder();

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