#fixed code
                             @Override
	public List<?> getClasses(){
		LabelEncoder labelEncoder = getLabelEncoder();

		return labelEncoder.getClasses();
	}
#vulnerable code 
                             @Override
	public List<?> getClasses(){
		List<Object> result = new ArrayList<>();

		List<?> values = (List<?>)get("classes_");
		for(Object value : values){

			if(value instanceof HasArray){
				HasArray hasArray = (HasArray)value;

				result.addAll(hasArray.getArrayContent());
			} else

			{
				result.add(value);
			}
		}

		return result;
	} 
                            #location 6 
                            #vulnerability type NULL_DEREFERENCE