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<document>
<body>
<section name="BCEL">
<p>
The Byte Code Engineering Library (Apache Commons BCEL™) is intended to give users a
convenient way to analyze, create, and manipulate (binary)
Java class files (those ending with .class). Classes are
represented by objects which contain all the symbolic information
of the given class: methods, fields and byte code instructions, in
particular.
</p>
<p>
Such objects can be read from an existing file, be transformed
by a program (e.g. a class loader at run-time) and written to a file again.
An even more interesting application is the creation of classes from scratch
at run-time. The Byte Code Engineering Library (BCEL) may be also useful
if you want to learn about the Java Virtual Machine (JVM) and the format of
Java .class files.
</p>
<p>
BCEL contains a byte code verifier named JustIce, which usually
gives you much better information about what's wrong with your
code than the standard JVM message.
</p>
<p>
BCEL is already being used successfully in several projects such
as compilers, optimizers, obsfuscators, code generators
and analysis tools. Unfortunately there hasn't been much development
going on over the past few years. Feel free to help out or you
might want to have a look into the ASM project at objectweb.
</p>
</section>
</body>
</document>