#java #parsing #class


A Rust library that reads, writes, and parses Java Virtula Machine class files

3 unstable releases

Uses old Rust 2015

0.2.1 Jun 17, 2018
0.2.0 Jul 28, 2015
0.1.0 Jul 24, 2015

#12 in #class

23 downloads per month


1.5K SLoC


Parses the class file format that is used by the Java Virtual Machine version 8.


extern crate classreader;

use classreader::ClassReader;
use std::fs::File;

pub fn main() {
    let mut file = File::open("pkg/Test.class").unwrap();
    let class = ClassReader::new_from_reader(file).unwrap();

    assert_eq!(0xCAFEBABE, class.magic);

classreader uses the log crate to emit some log messages. They are mainly useful for low level debugging.


Parses the whole rt.jar of OpenJDK 8 without issue. Code is not yet decoded. Apart from that, everything is parsed into suitable data structures.


Strings from a class file's constant pool are currently parsed into a Rust String. It seems that class files may contain code points for surrogate pairs. These are invalid for UTF-8 encoded strings which is what Rust uses. So whenever such a code point is decoded, it is replaced by the Unicode Replacement Character U+FFFD. This happens rarely but it does happen. A log message with info level is emitted.


Apache License Version 2. See LICENSE for the text.