{"record":{"id":"b3fd8f00e50c5160","repo":"stanfordnlp/CoreNLP","slug":"this-code-branch-left-blank-because-we-do-not-unde","errorCode":null,"errorMessage":"This code branch left blank because we do not understand what this method should do.","messagePattern":"This code branch left blank because we do not understand what this method should do\\.","errorType":"exception","errorClass":"java.lang.UnsupportedOperationException","httpStatus":null,"severity":"error","filePath":"src/edu/stanford/nlp/ling/CoreLabel.java","lineNumber":315,"sourceCode":"        if (oldLabel instanceof HasTag)\n          label.setTag(((HasTag) oldLabel).tag());\n        if (oldLabel instanceof HasOffset) {\n          label.setBeginPosition(((HasOffset) oldLabel).beginPosition());\n          label.setEndPosition(((HasOffset) oldLabel).endPosition());\n        }\n        if (oldLabel instanceof HasCategory)\n          label.setCategory(((HasCategory) oldLabel).category());\n        if (oldLabel instanceof HasIndex)\n          label.setIndex(((HasIndex) oldLabel).index());\n\n        label.setValue(oldLabel.value());\n\n        return label;\n      }\n    }\n\n    @Override\n    public Label newLabelFromString(String encodedLabelStr) {\n      throw new UnsupportedOperationException(\"This code branch left blank\" +\n      \" because we do not understand what this method should do.\");\n    }\n\n  }\n\n\n  /**\n   * Return a factory for this kind of label\n   *\n   * @return The label factory\n   */\n  public static LabelFactory factory() {\n    return new CoreLabelFactory();\n  }\n\n  /**\n   * {@inheritDoc}","sourceCodeStart":297,"sourceCodeEnd":333,"githubUrl":"https://github.com/stanfordnlp/CoreNLP/blob/1b7edd19c4d0d7b1f13a2591425b9b60a0b1af7a/src/edu/stanford/nlp/ling/CoreLabel.java#L297-L333","documentation":"The CoreLabel factory (labelFactory) implements Label.newLabelFromString as a deliberately unimplemented stub: it throws UnsupportedOperationException with a message stating the branch was left blank because the intended semantics were unclear. There is no input that avoids this; the operation simply does not exist on this factory.","triggerScenarios":"Calling CoreLabel.Factory (CoreLabel.labelFactory()).newLabelFromString(String) — or routing any code path (e.g. generic Label serialization/reconstruction utilities) through it.","commonSituations":"Generic code that calls newLabelFromString on any Label implementation (e.g. valueOf-style frameworks) hitting a CoreLabel factory; porting code that used LabelFactory.valueof or StringLabel-style factories.","solutions":["Do not call newLabelFromString on the CoreLabel factory; create labels with new CoreLabel(word) or new CoreLabel(String word, String tag) instead.","Parse the string yourself and construct a CoreLabel (e.g. new CoreLabel(value)) rather than delegating to the factory method.","If you need factory-based string reconstruction, use a Label implementation that supports it (e.g. StringLabel/Word via their factories), or convert after construction."],"exampleFix":"// before\nLabel label = CoreLabel.labelFactory().newLabelFromString(\"dog\"); // always throws\n// after\nCoreLabel label = new CoreLabel(\"dog\");","handlingStrategy":"fallback","validationCode":"// java\nLabel.Factory f = label.factory();\nLabel l;\ntry {\n  l = f.newLabelFromString(s);\n} catch (UnsupportedOperationException e) {\n  l = new CoreLabel(s);\n}","typeGuard":"// java\nstatic boolean supportsNewLabelFromString(Label.Factory f) {\n  return !(f instanceof CoreLabel.Factory);\n}","tryCatchPattern":"// java\nLabel label;\ntry {\n  label = factory.newLabelFromString(s);\n} catch (UnsupportedOperationException e) {\n  label = new CoreLabel(s); // explicit construction fallback\n}","preventionTips":["Never rely on newLabelFromString for CoreLabel; treat it as unimplemented.","Centralize label creation in one helper so you can choose constructors per implementation.","Document that CoreLabel.Factory only supports newLabel(String) and newLabel(Label) style creation."],"tags":["nlp","corelabel","not-implemented","factory"],"backgroundTag":"method-not-implemented","analyzedSha":"1b7edd19c4d0d7b1f13a2591425b9b60a0b1af7a","analyzedAt":"2026-09-10T02:24:07.274Z","contentChangedAt":"2026-09-10T02:24:07.274Z","schemaVersion":2},"datasetVersion":"2026-09-15T23:17:13.987Z"}