Table of contents

A classifier is a machine learning tool that will take data items and place them into one of k classes. A probabilistic classifier, like this one, can also give a probability distribution over the class assignment for a data item. This software is a Java implementation of a maximum entropy classifier. Maximum entropy models are otherwise known as softmax classifiers and are essentially equivalent to multiclass logistic regression models (though parameterized slightly differently, in a way that is advantageous with sparse explanatory feature vectors). In other words, this is the same basic technology that you’re usually getting in various of the cloud-based machine learning APIs (Amazon, Google, …) The classification method is described in:

Christopher Manning and Dan Klein. 2003. Optimization, Maxent Models, and Conditional Estimation without Magic. Tutorial at HLT-NAACL 2003 and ACL 2003. pdf slides pdf handouts

Version 2 of the classifier was developed by Anna Rafferty, Alex Kleeman, Jenny Finkel, and Christopher Manning.

The software requires requires Java (now Java 8). As well as API access, the program includes an easy-to-use command-line interface, ColumnDataClassifier, for building models. Its features are especially suited to building models over text data, but it also supports numeric variables.

Licensing. The Stanford Classifier is available for download, licensed under the GNU General Public License (v2 or later). Source is included. The Stanford Classifier code is dual licensed (in a similar manner to MySQL, etc.). Open source licensing is under the full GPL, which allows many free uses. For distributors of proprietary software, commercial licensing is available. If you don’t need a commercial license, but would like to support maintenance of these tools, we welcome gift funding.

The download is a 9.6 MB zipped file. If you unpack that file, you should have everything needed, including example files and documentation. Start by reading the README.txt file. Send any questions or feedback to


An introduction to the classifier and some examples of its use are available on our Wiki page. You can also look at the javadoc for ColumnDataClassifier.

Extensions: Packages by others using the Stanford Classifier


The Stanford Classifier is included in the most recent versions of CoreNLP.


Have a support question, PR, or bug report? Please post an issue on our Github

Feedback and licensing issues can also be sent to our mailing lists (see immediately below).

Mailing Lists

We have 3 mailing lists for the Stanford Classifier all of which are shared with other JavaNLP tools (with the exclusion of the parser). Each address is at

  1. java-nlp-user This is the best list to post to in order to send feature requests, make announcements, or for discussion among JavaNLP users. (Please ask support questions on Github.) You have to subscribe to be able to use this list. Join the list via this webpage or by emailing (Leave the subject and message body empty.) You can also look at the list archives.

  2. java-nlp-announce This list will be used only to announce new versions of Stanford JavaNLP tools. So it will be very low volume (expect 2-4 messages a year). Join the list via this webpage or by emailing (Leave the subject and message body empty.)

  3. java-nlp-support This list goes only to the software maintainers. It’s a good address for licensing questions, etc. For general use and support questions, you’re better off using Github or joining and using java-nlp-user. You cannot join java-nlp-support, but you can mail questions to

Release history

There is a standalone distribution of the classifier which has not been updated in some time.

Download Stanford Classifier version 4.2.0

4.2.02020‑11‑17Update for compatibility
4.0.02020‑04‑19Update for compatibility
3.9.22018‑10‑16Updated for compatibility
3.9.12018‑02‑27Updated for compatibility
3.8.02017‑06‑09Updated for compatibility
3.7.02016‑10‑31Update for compatibility
3.6.02015‑12‑09Updated for compatibility
3.5.22015‑04‑20Updated for compatibility
3.5.12015‑01‑29New input / output format options; support for GloVe word vector features
3.5.02014‑10‑26Upgrade to Java 8
3.4.12014‑08‑27Updated for compatibility with other Stanford releases
3.42014‑06‑16Updated for compatibility with other Stanford releases
3.3.12014‑01‑04Bugfix release
3.3.02013‑11‑12Updated for compatibility with other Stanford releases
3.2.02013‑06‑20Updated for compatibility with other Stanford releases
2.1.82013‑04‑04Updated for compatibility with other Stanford releases
2.1.72012‑11‑11Pair of word features added
2.1.62012‑07‑09Minor bug fixes
2.1.52012‑05‑22Updated for compatibility with other Stanford releases
2.1.42012‑03‑09Bugfix for svmlight format
2.1.32011‑12‑22Updated for compatibility with other Stanford releases
2.1.22011‑09‑14Change ColumnDataClassifier to be an object with API rather than static methods; ColumnDataClassifier thread safe
2.1.12011‑06‑19Updated for compatibility with other Stanford releases
2.12011‑05‑15Updated with more documentation
2.02007‑08‑15New command line interface, substantial increase in options and features (updated on 2007-09-28 with a bug fix)
1.02003‑05‑26Initial release