apache/hadoop · error · RuntimeException

Can't create MD5 digests

Error message

Can't create MD5 digests

What it means

Error "Can't create MD5 digests" thrown in apache/hadoop.

Source

Thrown at hadoop-tools/hadoop-rumen/src/main/java/org/apache/hadoop/tools/rumen/RandomSeedGenerator.java:55

 * random numbers with better theoretical guarantees, see
 * P. L'Ecuyer, R. Simard, E. J. Chen, and W. D. Kelton, 
 * ``An Objected-Oriented Random-Number Package with Many Long Streams and 
 * Substreams'', Operations Research, 50, 6 (2002), 1073--1075
 * http://www.iro.umontreal.ca/~lecuyer/papers.html
 * http://www.iro.umontreal.ca/~lecuyer/myftp/streams00/
 */
public class RandomSeedGenerator {
  private static Logger LOG = LoggerFactory.getLogger(RandomSeedGenerator.class);

  /** MD5 algorithm instance, one for each thread. */
  private static final ThreadLocal<MessageDigest> md5Holder =
      new ThreadLocal<MessageDigest>() {
        @Override protected MessageDigest initialValue() {
          MessageDigest md5 = null; 
          try {
            md5 = MessageDigest.getInstance("MD5");
          } catch (NoSuchAlgorithmException nsae) {
            throw new RuntimeException("Can't create MD5 digests", nsae);
          }
          return md5;
        }
      };
      
  /**
   * Generates a new random seed.
   *
   * @param streamId a string identifying the stream of random numbers
   * @param masterSeed higher level master random seed
   * @return the random seed. Different (streamId, masterSeed) pairs result in
   *         (vastly) different random seeds.
   */   
  public static long getSeed(String streamId, long masterSeed) {
    MessageDigest md5 = md5Holder.get();
    md5.reset();
    //'/' : make sure that we don't get the same str from ('11',0) and ('1',10)
    // We could have fed the bytes of masterSeed one by one to md5.update()

View on GitHub (pinned to 2add963021)

Solutions

1. Run on a JRE that provides the MD5 MessageDigest algorithm (any standard JDK does).

When it happens

Trigger: The JVM's MessageDigest does not support MD5 when RandomSeedGenerator initializes, an environment/JCE configuration problem.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/670314996303c7cf. Report an issue: GitHub.