"The method addAttribute(Class) is undefined for the type TokenStream" while using Apache Lucene in Java

Question

I am using Apache Lucene for tokenizing string in Java and I am encountering the below error even after importing all the external jar files.

The error is:

The method addAttribute(Class) is undefined for the type TokenStream

The line of code in which the error occured:

CharTermAttribute charTermAttri=stream.addAttribute(CharTermAttribute.class);

The code is:

public static ArrayList<String> tokenizeString(Analyzer analyzer, String string) {
        ArrayList<String> result = new ArrayList<String>();

        try {
          TokenStream stream = analyzer.tokenStream(null, new StringReader(string));
          **CharTermAttribute charTermAttri = stream.addAttribute(CharTermAttribute.class);**
          stream.reset();
          while (stream.incrementToken()) {
            result.add(stream.getAttribute(CharTermAttribute.class).toString());
          }
          stream.close();
        } catch (IOException e) {
          // not thrown b/c we're using a string reader...
          throw new RuntimeException(e);
        }
        return result;
      }