code: public final void evalError() throws IOException {
      final List<EvaluationMonitor<SequenceLabelSample>> listeners = new LinkedList<EvaluationMonitor<SequenceLabelSample>>();
      listeners.add(new SequenceLabelerEvaluationErrorListener());
      final SequenceLabelerEvaluator evaluator = new SequenceLabelerEvaluator(this.corpusFormat,
          this.sequenceLabeler, listeners
              .toArray(new SequenceLabelerEvaluationMonitor[listeners.size()]));
      evaluator.evaluate(this.testSamples);
      System.out.println(evaluator.getFMeasure());
    }
docs: Evaluate and print every error.
  
  @throws IOException
  if test corpus not loaded