Sentence Detection Example in openNLP using Java

What is Sentence Detection

Sentence Detection or Sentence Segmentation is a process of finding the start and end of a sentence (in a paragraph). This has to be done often in pre-processing section of most of the use cases, which are trying to be solved using Natural Language Processing techniques. Furthermore, Sentence Detection is one of the problems in Natural Language Processing.

Sentence detection is quite challenging because of many reasons in which one of them is : Period symbol (.) which usually denotes the end of a sentence, could also come in an email addresses, abbreviations, decimals etc.,

Sentence Detection Example in openNLP

The following example, shows how to use SentenceDetectorME class to detect sentences in a paragraph/string. If you would like to know how to setup eclipse project, refer to setup of java project with openNLP libraries, in eclipse. The process should be same, even for a different IDE(adding the required jars to the build path should do the magic).

When SentenceDetectExample,java is run, the console output is :

The project structure and model file location, etc., for the example is shown below:

Sentence Detection Example in openNLP - example project structure - Tutorialkart

Example Project – Structure

Model File:

The model file en-sent.bin is available at Stay updated regarding latest releases of openNLP or model files, at

Java Documentation

Find the java documentation for SentenceDetectorME at official site and play with the other methods like getSentenceProbabilities(), sentPosDetect(String s), etc., for a better understanding.

Custom model for Sentence Detection from user defined training data

If you are interested in knowing of how to train and generate a model yourself for Sentence Detection, refer to training a model for Sentence Detection in openNLP.

Conclusion :

In this openNLP tutorial, we have seen Sentence Detection Example in openNLP using Java.