MuntashirAkon/AppManager · error · IOException

Premature end of data

Error message

Premature end of data

What it means

ByteUtils.fromLittleEndian(InputStream,int) reads `length` bytes little-endian from a stream and throws this IOException when the stream ends (read() returns -1) before all requested bytes are consumed — i.e. the data is truncated.

Source

Thrown at app/src/main/java/org/apache/commons/compress/utils/ByteUtils.java:97

    }

    /**
     * Reads the given number of bytes from the given stream as a little endian long.
     * @param in the stream to read from
     * @param length the number of bytes representing the value
     * @return the number read
     * @throws IllegalArgumentException if len is bigger than eight
     * @throws IOException if reading fails or the stream doesn't
     * contain the given number of bytes anymore
     */
    public static long fromLittleEndian(final InputStream in, final int length) throws IOException {
        // somewhat duplicates the ByteSupplier version in order to save the creation of a wrapper object
        checkReadLength(length);
        long l = 0;
        for (int i = 0; i < length; i++) {
            final long b = in.read();
            if (b == -1) {
                throw new IOException("Premature end of data");
            }
            l |= (b << (i * 8));
        }
        return l;
    }

    /**
     * Reads the given number of bytes from the given supplier as a little endian long.
     *
     * <p>Typically used by our InputStreams that need to count the
     * bytes read as well.</p>
     *
     * @param supplier the supplier for bytes
     * @param length the number of bytes representing the value
     * @return the number read
     * @throws IllegalArgumentException if len is bigger than eight
     * @throws IOException if the supplier fails or doesn't supply the
     * given number of bytes anymore

View on GitHub (pinned to 0152f468fc)

Solutions

1. Check the stream has at least `length` bytes available before reading (or use DataInputStream.readFully with try/catch for EOF)
2. Verify the source file/stream integrity and re-transfer if truncated
3. Catch IOException and treat as end-of-data / corrupt input, aborting the parse

Example fix

// before
long size = ByteUtils.fromLittleEndian(in, 8); // throws on truncated stream
// after
byte[] buf = new byte[8];
int n = in.readNBytes(buf, 0, 8);
if (n < 8) throw new TruncatedDataException("expected 8 bytes, got " + n);
long size = ByteUtils.fromLittleEndian(buf);

if (in.available() > 0 && in.available() < length) { /* likely truncated: handle before reading */ }

try { long v = ByteUtils.fromLittleEndian(in, length); } catch (IOException e) { if (e.getMessage().equals("Premature end of data")) { throw new TruncatedArchiveException("stream ended before " + length + " bytes"); } throw e; }

When it happens

Trigger: Calling fromLittleEndian(InputStream, length) when fewer than `length` bytes remain before EOF, e.g. reading a fixed-size header from a truncated or corrupt file.

Common situations: Parsing archive headers from truncated downloads; reading past the last entry in a stream; files cut off by transfer interruption.

Related errors

• Detect premature EOF
• Failed to sign
• Could not cache the APK file
• Could not get backup files.
• Could not retrieve metadata from backup.

AI-assisted analysis of MuntashirAkon/AppManager@0152f468fc (2026-09-12). Data as JSON: /api/errors/7e68671d3e4937a2. Report an issue: GitHub.