apache/hadoop · error · UnsupportedOperationException

Byte-buffer read unsupported by ${className}

Error message

Byte-buffer read unsupported by ${className}

What it means

Error "Byte-buffer read unsupported by ${className}" thrown in apache/hadoop.

Source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FSDataInputStream.java:160

  
  /**
   * Get a reference to the wrapped input stream. Used by unit tests.
   *
   * @return the underlying input stream
   */
  @InterfaceAudience.Public
  @InterfaceStability.Stable
  public InputStream getWrappedStream() {
    return in;
  }

  @Override
  public int read(ByteBuffer buf) throws IOException {
    if (in instanceof ByteBufferReadable) {
      return ((ByteBufferReadable)in).read(buf);
    }

    throw new UnsupportedOperationException("Byte-buffer read unsupported " +
            "by " + in.getClass().getCanonicalName());
  }

  @Override
  public FileDescriptor getFileDescriptor() throws IOException {
    if (in instanceof HasFileDescriptor) {
      return ((HasFileDescriptor) in).getFileDescriptor();
    } else if (in instanceof FileInputStream) {
      return ((FileInputStream) in).getFD();
    } else {
      return null;
    }
  }

  @Override
  public void setReadahead(Long readahead)
      throws IOException, UnsupportedOperationException {
    try {

View on GitHub (pinned to 2add963021)

Solutions

1. Use the byte-array read() APIs instead of ByteBuffer reads.
2. Check hasCapability("in:readbytebuffer") before calling ByteBuffer read.
3. Provide a HasEnhancedByteBufferAccess-capable stream from the filesystem implementation.

When it happens

Trigger: Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FSDataInputStream.java:160 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/5edd183d2b4b59b3. Report an issue: GitHub.