apache/hadoop · error · IllegalArgumentException

Invalid pattern: {regex}

Error message

Invalid pattern: {regex}

What it means

Error "Invalid pattern: {regex}" thrown in apache/hadoop.

Source

Thrown at hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/lib/input/SequenceFileInputFilter.java:122

    public Configuration getConf() {
      return conf;
    }
  }
    
  /** Records filter by matching key to regex
   */
  public static class RegexFilter extends FilterBase {
    private Pattern p;
    /** Define the filtering regex and stores it in conf
     * @param conf where the regex is set
     * @param regex regex used as a filter
     */
    public static void setPattern(Configuration conf, String regex)
        throws PatternSyntaxException {
      try {
        Pattern.compile(regex);
      } catch (PatternSyntaxException e) {
        throw new IllegalArgumentException("Invalid pattern: "+regex);
      }
      conf.set(FILTER_REGEX, regex);
    }
        
    public RegexFilter() { }
        
    /** configure the Filter by checking the configuration
     */
    public void setConf(Configuration conf) {
      String regex = conf.get(FILTER_REGEX);
      if (regex == null)
        throw new RuntimeException(FILTER_REGEX + "not set");
      this.p = Pattern.compile(regex);
      this.conf = conf;
    }


    /** Filtering method

View on GitHub (pinned to 2add963021)

Solutions

1. Set mapreduce.input.sequencefileinputfilter.regex to a valid Java regular expression.

When it happens

Trigger: Thrown at hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/lib/input/SequenceFileInputFilter.java:122 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/ca6c7c69c47a2ebe. Report an issue: GitHub.