apache/hadoop · error · IOException

Path is null

Error message

Path is null

What it means

NativeIO.getStat(String path) refuses a null argument up front: it logs 'Path is null' and throws IOException. It is a precondition guard so the JNI layer never receives a null pointer, which would produce a crash or an opaque native error. The real bug is upstream — wherever the null path originated.

Source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/nativeio/NativeIO.java:613

          }
        }
      }
      return stat;
    }

    /**
     * Return the file stat for a file path.
     *
     * @param path  file path
     * @return  the file stat
     * @throws IOException  thrown if there is an IO error while obtaining the
     * file stat
     */
    public static Stat getStat(String path) throws IOException {
      if (path == null) {
        String errMessage = "Path is null";
        LOG.warn(errMessage);
        throw new IOException(errMessage);
      }
      Stat stat = null;
      try {
        if (!Shell.WINDOWS) {
          stat = stat(path);
          stat.owner = getName(IdCache.USER, stat.ownerId);
          stat.group = getName(IdCache.GROUP, stat.groupId);
        } else {
          stat = stat(path);
        }
      } catch (NativeIOException nioe) {
        LOG.warn("NativeIO.getStat error ({}): {} -- file path: {}",
            nioe.getErrorCode(), nioe.getMessage(), path);
        throw new PathIOException(path, nioe);
      }
      return stat;
    }

View on GitHub (pinned to 2add963021)

Solutions

1. Null-check the path at its source and fail with context naming the config key or field that was null.
2. Use Objects.requireNonNull(path, "path") to fail fast at the caller with a better message than the IO guard.
3. Trace the producer: log the variable right before passing it so the null's origin is visible.

Example fix

// before
Stat st = NativeIO.getStat(maybeNullPath);

// after
Stat st = NativeIO.getStat(
    Objects.requireNonNull(path, "path must be set (source: config 'data.dir')"));

if (path == null) {
  throw new IllegalArgumentException("path required (source: " + sourceName + ")");
}
Stat st = NativeIO.getStat(path);

When it happens

Trigger: Calling NativeIO.getStat(null), typically with a null produced earlier: File.getParent() at a root path returning null, a missing config property, Map.get() returning null, or Optional-style access on an absent value.

Common situations: Path derivation like file.getParent() on root-relative files; typo'd configuration keys yielding null; data structures populated conditionally so the key is sometimes absent.

Related errors

• key cannot be null
• key can not be null
• Key may not be null
• Failed to rename %s to %s, file already exists or not empty!
• tokenStr cannot be null

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/00db5d6cc3f99c73. Report an issue: GitHub.