error loading NER .bin file as model argument for openNLP::Maxent_Entity_Annotator()

Question

I created a model using Apache OpenNLP's command line tool to recognize named entities. The below code created the model using the file sentences4OpenNLP.txt as a training set.

opennlp TokenNameFinderTrainer -type maxent -model C:\Users\Documents\en-ner-org.bin -lang en -data C:\Users\Documents\apache-opennlp-1.6.0\sentences4OpenNLP.txt -encoding UTF-8

I tested the model from the command line by passing it sentences to tag, and the model seemed to be working well. However, I am unable to successfully use the model from R. I am using the below lines in attempts to create an organization annotating function. Using the same code to load a model downloaded from OpenNLP works fine.

modelNER <- "C:/Users/Documents/en-ner-org.bin"
oa <- openNLP::Maxent_Entity_Annotator(language = "en",
                                  kind = "organization",
                                  probs = TRUE,
                                  model = modelNER)

When the above code is run I get an error saying:

Could not instantiate the opennlp.tools.namefind.TokenNameFinderFactory. The initialization throw an exception.
opennlp.tools.util.ext.ExtensionNotLoadedException: Unable to find implementation for opennlp.tools.util.BaseToolFactory, the class or service opennlp.tools.namefind.TokenNameFinderFactory could not be located!
     at opennlp.tools.util.ext.ExtensionLoader.instantiateExtension(ExtensionLoader.java:97)
     at opennlp.tools.util.BaseToolFactory.create(BaseToolFactory.java:106)
     at opennlp.tools.util.model.BaseModel.initializeFactory(BaseModel.java:254)
Error in .jnew("opennlp.tools.namefind.TokenNameFinderModel", .jcast(.jnew("java.io.FileInputStream",  : 
java.lang.IllegalArgumentException: opennlp.tools.util.InvalidFormatException: Could not instantiate the opennlp.tools.namefind.TokenNameFinderFactory. The initialization throw an exception.
     at opennlp.tools.util.model.BaseModel.loadModel(BaseModel.java:237)
     at opennlp.tools.util.model.BaseModel.<init>(BaseModel.java:181)
     at opennlp.tools.namefind.TokenNameFinderModel.<init>(TokenNameFinderModel.java:110)

Any advice on how to fix the error would be a big help. Thanks in advance.

Answer 1

Resolved the error. The R function openNLP::Maxent_Entity_Annotator was not compatible with the named entity recognition (NER) model being produced by OpenNLP 1.6.0. Building the NER model using OpenNLP 1.5.3 resulted in openNLP::Maxent_Entity_Annotator running without error.