MuntashirAkon/AppManager · error · IOException

for file

Error message

 for file 

What it means

writeMetadataV5 writes meta_v5.am.json by serializing metadata.metadata via serializeToJson(); any JSONException is rethrown as IOException with the metadata file path appended, indicating the v5 metadata document could not be serialized to JSON.

Source

Thrown at app/src/main/java/io/github/muntashirakon/AppManager/backup/MetadataManager.java:143

            // Info is a subset of meta_v2.am.json except for backup_name
            metadataObject.remove("backup_name");
            outputStream.write(metadataObject.toString(4).getBytes());
            return Collections.singletonMap(metadataFile.getName(), DigestUtils.getHexDigest(
                    metadata.info.checksumAlgo, metadataFile));
        } catch (JSONException e) {
            throw new IOException(e.getMessage() + " for path " + backupFile.getBackupPath(), e);
        }
    }

    @WorkerThread
    @NonNull
    private static Map<String, String> writeMetadataV5(@NonNull BackupMetadataV5 metadata, @NonNull BackupItems.BackupItem backupFile) throws IOException {
        Map<String, String> filenameChecksumMap = new LinkedHashMap<>(2);
        Path metadataFile = backupFile.getMetadataV5File(true);
        try (OutputStream outputStream = metadataFile.openOutputStream()) {
            outputStream.write(metadata.metadata.serializeToJson().toString(4).getBytes());
        } catch (JSONException e) {
            throw new IOException(e.getMessage() + " for file " + metadataFile, e);
        }
        // Encrypt the metadata
        Path encryptedMetadataFile = backupFile.encrypt(new Path[]{metadataFile})[0];
        filenameChecksumMap.put(encryptedMetadataFile.getName(), DigestUtils.getHexDigest(
                metadata.info.checksumAlgo, encryptedMetadataFile));
        Path infoFile = backupFile.getInfoFile();
        try (OutputStream outputStream = infoFile.openOutputStream()) {
            outputStream.write(metadata.info.serializeToJson().toString(4).getBytes());
            filenameChecksumMap.put(infoFile.getName(), DigestUtils.getHexDigest(
                    metadata.info.checksumAlgo, infoFile));
        } catch (JSONException e) {
            throw new IOException(e.getMessage() + " for file " + infoFile, e);
        }
        return filenameChecksumMap;
    }

    private static void setCrypto(@NonNull BackupItems.BackupItem backupItem, @NonNull BackupMetadataV5.Info backupInfo) throws IOException {
        if (!CryptoUtils.isAvailable(backupInfo.crypto)) {

View on GitHub (pinned to 0152f468fc)

Solutions

1. Inspect the JSONException cause to find the field that failed to serialize and populate it with a valid value.
2. Validate the Metadata object (required fields non-null) before calling writeMetadata.
3. Reload the metadata from the source backup to recover a consistent in-memory object.

Example fix

// before
MetadataManager.writeMetadata(metadata, backupFile);
// after
if (metadata.metadata == null) {
    throw new IllegalArgumentException("Metadata body is null");
}
MetadataManager.writeMetadata(metadata, backupFile);

if (metadata.metadata == null || metadata.info == null) {
    throw new IllegalArgumentException("Incomplete BackupMetadataV5");
}

try {
    MetadataManager.writeMetadata(metadata, backupFile);
} catch (IOException e) {
    if (e.getCause() instanceof JSONException) {
        // fix the offending Metadata field reported by the cause
    } else throw e;
}

When it happens

Trigger: Calling writeMetadata for a v5+ backup when metadata.metadata.serializeToJson() throws — typically null or invalid field values inside the Metadata object.

Common situations: Programmatically constructed Metadata objects with missing/invalid fields (e.g. null timestamps or names placed where JSONObject.put rejects them), or corrupted in-memory metadata after partial deserialization.

Understand the failure class

Background: "JSON serialization failed", "not JSON serializable", "Failed to serialize": why JSON marshaling errors happen and how to fix them — this error's family across 46 libraries.

Related errors

• Empty JSON string for path
• for path
• Could not get backup files.
• Could not retrieve metadata from backup.
• Failed to create checksum file.

AI-assisted analysis of MuntashirAkon/AppManager@0152f468fc (2026-09-12). Data as JSON: /api/errors/49d2ee0d1b1aa33d. Report an issue: GitHub.