public static int converttoInt(byte[] bytes) {
        if (bytes.length != 4) {
            throw new IllegalArgumentException("Cannot convert to integer");
        }
        return ((0xff & bytes[0]) << 24) | ((0xff & bytes[1]) << 16) | ((0xff & bytes[2]) << 8) |
                (0xff & bytes[3]);
    }
Holds details on Apple ICNS icons
tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-image-module/src/main/java/org/apache/tika/parser/image/ICNSType.java