apache/flink · error · IndexOutOfBoundsException

Byte array does not provide enough space to store requested…

Error message

Byte array does not provide enough space to store requested data.

What it means

Thrown by DataInputDeserializer.read when the destination byte array cannot hold the requested range: b.length - off < len. The guard fires before any data is copied, indicating the caller-supplied buffer is too small for the requested offset/length.

Solutions

1. Size the destination array to at least off + len before calling read.
2. Use read(byte[]) with a correctly sized array.
3. Derive the destination length from the record's declared size, not a fixed constant.

Example fix

// before
byte[] dst = new byte[8];
input.read(dst, 0, recordLen); // recordLen > 8

// after
byte[] dst = new byte[recordLen];
input.read(dst, 0, recordLen);

if (off < 0 || len < 0 || b.length - off < len) {
    throw new IndexOutOfBoundsException("dst too small: len=" + len + ", off=" + off + ", cap=" + b.length);
}
input.read(b, off, len);

When it happens

Trigger: Calling read(b, off, len) where b.length - off < len (e.g. reading 16 bytes into an 8-byte array, or with a large offset that leaves insufficient room).

Common situations: Destination buffer sized too small for the record; an offset that eats into available space; mis-sizing a read buffer relative to the declared record length.

Related errors

• Invalid bounds.
• Length cannot be negative.
• Length may not be negative.
• Offset cannot be negative.
• Could not skip bytes.

AI-assisted analysis of apache/flink@2f3c205e92 (2026-08-14). Data as JSON: /api/errors/7aec0400424e42dd. Report an issue: GitHub.

Appendix: source

Thrown at flink-core/src/main/java/org/apache/flink/core/memory/DataInputDeserializer.java:393

        if (skippedBytes < numBytes) {
            throw new EOFException("Could not skip " + numBytes + " bytes.");
        }
    }

    @Override
    public int read(@Nonnull byte[] b, int off, int len) throws IOException {

        if (off < 0) {
            throw new IndexOutOfBoundsException("Offset cannot be negative.");
        }

        if (len < 0) {
            throw new IndexOutOfBoundsException("Length cannot be negative.");
        }

        if (b.length - off < len) {
            throw new IndexOutOfBoundsException(
                    "Byte array does not provide enough space to store requested data" + ".");
        }

        if (this.position >= this.end) {
            return len == 0 ? 0 : -1;
        } else {
            int toRead = Math.min(this.end - this.position, len);
            System.arraycopy(this.buffer, this.position, b, off, toRead);
            this.position += toRead;

            return toRead;
        }
    }

    @Override
    public int read(@Nonnull byte[] b) throws IOException {
        return read(b, 0, b.length);
    }

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