skylot/jadx · error · IOException

Zip file is too big

Error message

Zip file is too big

What it means

A hard size gate in JadxZipParser.load(). The custom parser memory-maps or fully buffers the archive into a single ByteBuffer, whose capacity is an int, so any file whose length is >= Integer.MAX_VALUE (~2 GiB) cannot be represented and is rejected before any mapping is attempted. This is an architectural limit of the custom parser, not the fallback parser.

Source

Thrown at jadx-commons/jadx-zip/src/main/java/jadx/zip/parser/JadxZipParser.java:138

	}

	private ByteBuffer getBuffer() {
		ByteBuffer buf = byteBuffer;
		if (buf == null) {
			throw new RuntimeException("File not opened: " + zipFile);
		}
		return buf;
	}

	private void load() throws IOException {
		if (byteBuffer != null) {
			// already loaded
			return;
		}
		RandomAccessFile raFile = new RandomAccessFile(zipFile, "r");
		long size = raFile.length();
		if (size >= Integer.MAX_VALUE) {
			throw new IOException("Zip file is too big");
		}
		int fileLen = (int) size;
		if (fileLen < 100 * 1024 * 1024) {
			// load files smaller than 100MB directly into memory
			byte[] bytes = new byte[fileLen];
			raFile.readFully(bytes);
			byteBuffer = ByteBuffer.wrap(bytes).order(ByteOrder.LITTLE_ENDIAN);
			raFile.close();
		} else {
			// for big files - use a memory mapped file
			file = raFile;
			fileChannel = raFile.getChannel();
			byteBuffer = fileChannel.map(FileChannel.MapMode.READ_ONLY, 0, fileChannel.size());
			byteBuffer.order(ByteOrder.LITTLE_ENDIAN);
		}
	}

	private List<IZipEntry> searchLocalFileHeaders(int maxEntriesCount) {

View on GitHub (pinned to e738a26571)

Solutions

1. If the file genuinely exceeds 2 GiB, the custom parser cannot handle it; split or shrink the archive (e.g., split per-ABI APKs, remove debug assets).
2. Confirm the file is actually a zip and not a different large binary mislabeled.
3. Use ZipReaderFlags.FALLBACK_AS_DEFAULT so jadx uses the streaming fallback parser which is not bound by the single-buffer int limit.
4. Reduce the archive below the threshold by removing unused content.

Example fix

// before
ZipContent content = zipReader.open(largeFile); // custom parser throws

// after
ZipReader reader = new ZipReader(EnumSet.of(ZipReaderFlags.FALLBACK_AS_DEFAULT));
ZipContent content = reader.open(largeFile);

// Reject files at/above the 2 GiB custom-parser limit before opening.
long MAX = (long) Integer.MAX_VALUE; // ~2 GiB
if (file.length() >= MAX) {
    throw new IOException("Zip too large for custom parser (>= 2 GiB): " + file.length());
}

try {
    content = zipReader.open(file);
} catch (IOException e) {
    if (e.getMessage().contains("too big")) {
        // switch to streaming fallback parser which is not int-capacity bound
        reader = new ZipReader(EnumSet.of(ZipReaderFlags.FALLBACK_AS_DEFAULT));
        content = reader.open(file);
    } else {
        throw e;
    }
}

When it happens

Trigger: Opening an archive whose RandomAccessFile.length() reports >= 2^31-1 bytes through the custom JadxZipParser. Files < 100 MiB are read into a heap byte[]; larger ones are memory-mapped, but both paths are gated by the same int-capacity check.

Common situations: Very large APKs, AABs, or supersets/zipped SDKs that exceed 2 GiB; a misidentified file (e.g., a disk image with a .zip extension); archives that grew past the limit after bundling many ABIs/assets.

Related errors

• {}
• Failed to open zip: {}
• Failed to process zip file: {}
• Failed to process zip entry: {}
• Failed to read bytes for entry: {}

AI-assisted analysis of skylot/jadx@e738a26571 (2026-08-14). Data as JSON: /api/errors/fcc28e791ff38095. Report an issue: GitHub.