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<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 3.0//EN">
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<html>
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<head>
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<title> JOchens' java-DEcompiler (JODE) </title>
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<meta name="description" content="The home page of jode, my Java decompiler.">
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<meta name="author" content="Jochen Hoenicke">
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<meta name="keywords" content="jode, java, decompile, decompiler,
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java-decompiler, reverse engineering, free, GPL">
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<meta name="robots" content="index">
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<meta name="robots" content="nofollow">
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<meta name="date" content="1999-03-08">
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</head>
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<body>
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<a href="../index.html">Home</a>
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<h2>What is it?</h2>
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<P>This is a decompiler for java I have written in my spare time. It
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takes class-files as input and produces something similar to the
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original java-File. Of course this can't be perfect: There is no way
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to produce the comments or the names of local variables (except when
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compiled with <code>-g</code>) and there are often more ways to write
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the same thing. But it does its job quite well.</P>
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<h2>Quick Test</h2>
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I have now an applet interface to the decompiler.
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<a href="jode-applet.html">Check it out</a>.
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<h2>How to get it</h2>
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<P>You can donwload the files in zip form.
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The <a href="jode_src.zip">sources</a> contain only the
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<code>java</code> files, the <a href="jode_cls.zip">classes</a>
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contain only the <code>class</code> files. </p>
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<p>I also have a <a href="jode.tar.gz">tar.gz file</a> containing only
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the <code>RCS</code> directories. This is the form I maintain the
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project, but you probably need unix and a few tools to use them.</p>
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<p>There are also some <a href="snapshot/">snapshots</a> that have new
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features like inner and anonymous classes. </p>
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<p><a href=".">Click here</a> to browse the files online.
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</p>
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<h2>How to use it</h2>
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<p>I have some simple step by step pages. There are three
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possibilities:
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<ul>
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<li> <a href="jode-useapplet.html"> Using the applet version</a>.
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This can make problem due to java's security policy, but is the
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simplest way and works on most platforms.
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</li>
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<li> If you use Windows, you should look on <a
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href="jode-win.html">this page</a>.</li>
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<li> Unix users should look on <a href="jode-unix.html">this page</a>.
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</ul>
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<h2>Known bugs</h2>
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<p>There may be situations, where the code doesn't understand complex
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expressions. In this many ugly temporary variables are used, but the
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code should still be compileable. This does especially happen when
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you compile with `-O' flag and javac has inlined some methods. </p>
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<p>Sometimes this program may exit with an <code>Exception</code> or
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produce incorrect code. Most time the code can't be compiled, so that
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it can be easily spotted. If you have one of these problems (except
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those that occur on some of the <code>jode.test</code> files, I would
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be very interested in a bug report (including the <code>class</code>
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file, if possible).</p>
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<p>Sometimes it generates some <code>GOTO</code> expression and
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labels. This can't be compiled, but shouldn't happen any more with
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javac or jikes.</p>
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<p>It doesn't handle inner and anonymous classes, yet. You can
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decompile them separately, though (use `<code>+$</code>' switch under
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jikes), but there is a bug in javac, so that a final variable is twice
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initialized. If you encounter this problem just remove the doubled
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line by hand. </p>
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<p><b>New!</b> The latest <a href="snapshot">snapshot</a> can handle
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inner and anonymous classes.</p>
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<h2>Why did I wrote it?</h2>
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<p>Someday I found <code>guavad</code>, a disassembler for java byte
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code (it does similar things like <code>javap -c</code>). I used
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it on a class file, and found that it was possible to reconstruct the
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original java code. First I did it by hand on some small routines,
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but I soon realized that it was a rather stupid task, and that I could
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write a <a href="../perl/dasm_to_java.perl"><code>perl</code> script</a>
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that does the same. At the end of the next day I had a working
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decompiler.</p>
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<p>Now while it was working, it was not easy to use. You had to
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decompile the code first with a disassembler, cut the method, you
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wanted to decompile and then run the perl script on it. So I decided
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to get some information of the class files and do this all
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automatically. I decided to write it in <code>java</code> now,
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because it suited best.</p>
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<p>Just for the records: the java code is now more than 50 times
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bigger than the original perl script and is still growing.</p>
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<h2>License</h2>
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<p>This code is under GNU GPL. That basically means, that you can copy
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or modify this code, as long as you put all your modification under
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the GPL again. <A HREF="http://www.gnu.org/copyleft/gpl.html"> Look
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here for the complete license</a>.</p>
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<hr>
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<p><A HREF="mailto:Jochen.Hoenicke@Informatik.Uni-Oldenburg.DE">
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http://www.informatik.uni-oldenburg.de/~delwi/jode/jode.html</A>, last
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updated on <em>17-Jun-1999</em>.</p>
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</body>
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</html>
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