OpenNLP Overview - OpenNLP

What is Open NLP?

NLP is a combination of tools used to get useful information from natural language sources such as web pages and text documents.

What is Open NLP?

Apache OpenNLP is an open-source Java library used to perform natural language text. Here you can build effective text processing service using this library.

OpenNLP offers various services like tokenization, sentence segmentation, part-of-speech tagging, named entity extraction, chunking, parsing, and co-reference resolution, etc.

Features of OpenNLP

Following are the notable features of OpenNLP −

  • Named Entity Recognition (NER) – This feature is used to extract names of locations, people and things even while processing queries.
  • Summarize – This feature is used to summarize Paragraphs, articles, documents or their collection in NLP.
  • Searching – This feature is used to search string or its synonyms can be identified in given text, even though the given word is altered or misspelled.
  • Tagging (POS) − Tagging in NLP is used to divide the text into various grammatical elements for further analysis.
  • Translation – This feature is used in translation helps in translating one language into another.
  • Information grouping – This feature helps to group the textual information in the content of the document, just like Parts of speech.
  • Natural Language Generation – This is used for generating information from a database and automating the information reports such as weather analysis or medical reports.
  • Feedback Analysis − Here, various types of feedbacks from people are collected, regarding the products, by NLP to analyze how well the product is successful in winning their hearts.
  • Speech recognition − Though it is difficult to analyze human speech, NLP has some builtin features for this requirement.


The Apache OpenNLP library offers various classes and interfaces to perform various tasks of natural language processing such as sentence detection, tokenization, finding a name, tagging the parts of speech, chunking a sentence, parsing, co-reference resolution, and document categorization.

Addition to this you can also train and evaluate our own models for any of these tasks.


Other than above library, OpenNLP also provides a Command Line Interface (CLI), useful to train and evaluate models. Let’s discuss this topic in detail in the last chapter of this tutorial.


Open NLP Models

You can find different types of predefined models to perform various NLP tasks. This set may includes models for different languages.

Downloading the models

Let’s follow below mentioned steps to download the predefined models provided by OpenNLP.

Step 1 − Open the index page of OpenNLP models by clicking the following link −

nlp model

Step 2 – After licking on the given link, you will get to see a list of components of various languages and the links to download them. Here, you can get the list of all the predefined models provided by OpenNLP.


Now, download all these models to the folder C:/OpenNLP_models/>, by clicking on their respective links. While, all these models are language dependent and while using these. But make sure that the model language matches with the language of the input text.

History of OpenNLP

  • In 2010, OpenNLP entered the Apache incubation.
  • In 2011, Apache OpenNLP 1.5.2 Incubating was released, and in the same year, it graduated as a top-level Apache project.
  • In 2015, OpenNLP was 1.6.0 released.

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