We used the POSModel class's getFactory method to get a POSTaggerFactory instance. We will use its getTagDictionary method to obtain its TagDictionary instance. This is illustrated here:

MutableTagDictionary tagDictionary =  
  (MutableTagDictionary)posTaggerFactory.getTagDictionary(); 

The MutableTagDictionary interface extends the TagDictionary interface. The TagDictionary interface possesses a getTags method, and the MutableTagDictionary interface adds a put method that allows tags to be added to the dictionary. These interfaces are implemented by the POSDictionary class.