apache/hadoop · error · AlreadyClosedException

compress called on closed compressor

Error message

compress called on closed compressor

What it means

Error "compress called on closed compressor" thrown in apache/hadoop.

Source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/compress/zlib/BuiltInGzipCompressor.java:88

  @Override
  public boolean finished() {
    // Only if the trailer is also written, it is thought as finished.
    return state == BuiltInGzipDecompressor.GzipStateLabel.FINISHED && deflater.finished();
  }

  @Override
  public boolean needsInput() {
    return deflater.needsInput() && state != BuiltInGzipDecompressor.GzipStateLabel.TRAILER_CRC;
  }

  @Override
  public int compress(byte[] b, int off, int len) throws IOException {
    if (finished()) {
      throw new IOException("compress called on finished compressor");
    }

    if (state == BuiltInGzipDecompressor.GzipStateLabel.ENDED) {
      throw new AlreadyClosedException("compress called on closed compressor");
    }

    int compressedBytesWritten = 0;

    // If we are not within uncompressed data yet, output the header.
    if (state == BuiltInGzipDecompressor.GzipStateLabel.HEADER_BASIC) {
      int outputHeaderSize = writeHeader(b, off, len);
      numExtraBytesWritten += outputHeaderSize;

      compressedBytesWritten += outputHeaderSize;

      if (outputHeaderSize == len) {
        return compressedBytesWritten;
      }

      off += outputHeaderSize;
      len -= outputHeaderSize;
    }

View on GitHub (pinned to 2add963021)

Solutions

1. Do not call compress() after close(); create a new BuiltInGzipCompressor if compression must resume.
2. Guard compress calls with a state check or try/finally so close() runs only after all compress() calls complete.

When it happens

Trigger: Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/compress/zlib/BuiltInGzipCompressor.java:88 when the library encounters an invalid state.

Common situations: Occurs when compress() is called after the compressor has been closed. Check the closed flag before use and do not reuse a compressor after close(); create a new instance instead.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/5856267b733a0fee. Report an issue: GitHub.