apache/hadoop · error · UnsupportedOperationException

does not support release buffer.

Error message

${className} does not support release buffer.

What it means

releaseBuffer(ByteBuffer) returns pooled buffers to the wrapped stream, so it requires `in instanceof HasEnhancedByteBufferAccess` — the same interface that governs obtaining such buffers. If the inner stream lacks it, UnsupportedOperationException naming the wrapped class is thrown.

Solutions

1. Only call releaseBuffer() for buffers actually returned by read(ByteBufferPool,...) on the same stream
2. Track the acquisition path (pooled vs byte[]) so the release path matches it
3. Catch UnsupportedOperationException in cleanup code so release failures never mask the primary result

Example fix

// before
if (buffer != null) {
  cryptoIn.releaseBuffer(buffer); // UOE if pooled reads unsupported
}

// after
if (buffer != null) {
  try {
    cryptoIn.releaseBuffer(buffer);
  } catch (UnsupportedOperationException e) {
    // pooled path never active on this stream; nothing to return
  }
}

try {
  in.releaseBuffer(buffer);
} catch (UnsupportedOperationException e) {
  // pooled path was never active on this stream; nothing to return
}

When it happens

Trigger: Calling releaseBuffer() on a CryptoInputStream that never handed out pooled buffers (inner stream lacks HasEnhancedByteBufferAccess); cleanup paths that release unconditionally after a read fell back to plain byte[] reads.

Common situations: Zero-copy readers whose buffer-release code does not track whether the acquisition actually succeeded through the pooled path.

Related errors

• does not support enhanced byte buffer access.
• does not support positioned reads with byte buffers.
• Cannot seek to a negative offset
• does not support positioned read.
• does not support positioned readFully.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/37c271eae1080fb3. Report an issue: GitHub.

Appendix: source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/crypto/CryptoInputStream.java:741

          + " does not support enhanced byte buffer access.");
    }
    final ByteBuffer buffer = ((HasEnhancedByteBufferAccess) in).
        read(bufferPool, maxLength, opts);
    if (buffer != null) {
      final int n = buffer.remaining();
      if (n > 0) {
        streamOffset += buffer.remaining(); // Read n bytes
        final int pos = buffer.position();
        decrypt(buffer, n, pos);
      }
    }
    return buffer;
  }

  @Override
  public void releaseBuffer(ByteBuffer buffer) {
    if (!(in instanceof HasEnhancedByteBufferAccess)) {
      throw new UnsupportedOperationException(in.getClass().getCanonicalName()
          + " does not support release buffer.");
    }
    ((HasEnhancedByteBufferAccess) in).releaseBuffer(buffer);
  }

  @Override
  public void setReadahead(Long readahead) throws IOException,
      UnsupportedOperationException {
    if (!(in instanceof CanSetReadahead)) {
      throw new UnsupportedOperationException(in.getClass().getCanonicalName()
          + " does not support setting the readahead caching strategy.");
    }
    ((CanSetReadahead) in).setReadahead(readahead);
  }

  @Override
  public void setDropBehind(Boolean dropCache) throws IOException,
      UnsupportedOperationException {

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