#vulnerable code 
                             @Override
	public List<Feature> initializeFeatures(SkLearnEncoder encoder){
		List<String> featureNames = getFeatureNames();
		String separator = getSeparator();
		Map<String, Integer> vocabulary = getVocabulary();

		Feature[] featureArray = new Feature[featureNames.size()];

		for(String featureName : featureNames){
			String key = featureName;
			String value = null;

			int index = featureName.indexOf(separator);
			if(index > -1){
				key = featureName.substring(0, index);
				value = featureName.substring(index + separator.length());
			}

			FieldName name = FieldName.create(key);

			DataField dataField = encoder.getDataField(name);
			if(dataField == null){

				if(value != null){
					dataField = encoder.createDataField(name, OpType.CATEGORICAL, DataType.STRING);
				} else

				{
					dataField = encoder.createDataField(name, OpType.CONTINUOUS, DataType.DOUBLE);
				}
			}

			Feature feature;

			if(value != null){
				PMMLUtil.addValues(dataField, Collections.singletonList(value));

				feature = new BinaryFeature(encoder, dataField, value);
			} else

			{
				feature = new ContinuousFeature(encoder, dataField);
			}

			featureArray[vocabulary.get(featureName)] = feature;
		}

		List<Feature> result = new ArrayList<>();
		result.addAll(Arrays.asList(featureArray));

		return result;
	} 
                            #location 16 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                             @Override
	public List<Feature> initializeFeatures(SkLearnEncoder encoder){
		List<? extends String> featureNames = getFeatureNames();
		String separator = getSeparator();
		Map<String, Integer> vocabulary = getVocabulary();

		Feature[] featureArray = new Feature[featureNames.size()];

		for(String featureName : featureNames){
			String key = featureName;
			String value = null;

			int index = featureName.indexOf(separator);
			if(index > -1){
				key = featureName.substring(0, index);
				value = featureName.substring(index + separator.length());
			}

			FieldName name = FieldName.create(key);

			DataField dataField = encoder.getDataField(name);
			if(dataField == null){

				if(value != null){
					dataField = encoder.createDataField(name, OpType.CATEGORICAL, DataType.STRING);
				} else

				{
					dataField = encoder.createDataField(name, OpType.CONTINUOUS, DataType.DOUBLE);
				}
			}

			Feature feature;

			if(value != null){
				PMMLUtil.addValues(dataField, Collections.singletonList(value));

				feature = new BinaryFeature(encoder, dataField, value);
			} else

			{
				feature = new ContinuousFeature(encoder, dataField);
			}

			featureArray[vocabulary.get(featureName)] = feature;
		}

		List<Feature> result = new ArrayList<>();
		result.addAll(Arrays.asList(featureArray));

		return result;
	}