Lemmatizer (Apache OpenNLP Tools 1.9.5 API)
Date: 2026-06-18

opennlp.tools.lemmatizer

## Interface Lemmatizer

- All Known Implementing Classes:
    DictionaryLemmatizer, LemmatizerME

      public interface Lemmatizer

  The interface for lemmatizers.

- - ### Method Summary

    All Methods Instance Methods Abstract Methods
    Modifier and Type | Method and Description
    --- | ---
    `List<List<String>>` | `lemmatize(List<String> toks, List<String> tags)` Generates a lemma tags for the word and postag returning the result in a list of every possible lemma for each token and postag.
    `String[]` | `lemmatize(String[] toks, String[] tags)` Generates lemmas for the word and postag returning the result in an array.

- - ### Method Detail

    - #### lemmatize

          String[] lemmatize(String[] toks,
                             String[] tags)

      Generates lemmas for the word and postag returning the result in an array.
      Parameters:
        `toks` - an array of the tokens
        `tags` - an array of the pos tags
      Returns:
        an array of possible lemmas for each token in the sequence.

    - #### lemmatize

          List<List<String>> lemmatize(List<String> toks,
                                       List<String> tags)

      Generates a lemma tags for the word and postag returning the result in a list of every possible lemma for each token and postag.
      Parameters:
        `toks` - an array of the tokens
        `tags` - an array of the pos tags
      Returns:
        a list of every possible lemma for each token in the sequence.

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