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<html>
<HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
<TITLE>Read Me First</TITLE>
</HEAD>
<body>
<h1>Javassist version 2</h1>
<h3>in May, 2003.
<br>Copyright (C) 2000-2003 by Shigeru Chiba, All rights reserved.</h3>
<p><br></p>
<p>Javassist (JAVA programming ASSISTant) makes Java bytecode manipulation
simple. It is a class library for editing bytecodes in Java;
it enables Java programs to define a new class at runtime and to
modify a class file when the JVM loads it. Unlike other similar
bytecode editors, Javassist provides two levels of API: source level
and bytecode level. If the users use the source-level API, they can
edit a class file without knowledge of the specifications of the Java
bytecode. The whole API is designed with only the vocabulary of the
Java language. You can even specify inserted bytecode in the form of
source text; Javassist compiles it on the fly. On the other hand, the
bytecode-level API allows the users to directly edit a class file as
other editors.
<p><br>
<h2>Files</h2>
<ul>
<table>
<tr>
<td><li><tt><a href="License.html">License.html</a></tt></td>
<td>License file
(Also see the <a href="#copyright">copyright notices</a> below)</td>
</tr>
<tr>
<td><li><tt><a href="tutorial/tutorial.html">tutorial/tutorial.html</a></tt></td>
<td>Tutorial</td>
</tr>
<tr>
<td><li><tt>./javassist.jar</tt></td>
<td>The Javassist jar file (class files)</td>
</tr>
<tr>
<td><li><tt>./src/main</tt></td>
<td>The source files</td>
</tr>
<tr>
<td><li><tt><a href="html/index.html">html/index.html</a></tt></tr>
<td>The top page of the Javassist API document.</td>
</tr>
<tr>
<td><li><tt>./sample/</tt></td>
<td>Sample programs</td>
</tr>
</table>
</ul>
<p>To extract source files from the archive, use the jar command:<br>
<ul><pre>% jar xvf javassist-src.zip</pre></ul>
<p><br>
<h2>How to run sample programs</h2>
<p>JDK 1.2.2 or later is needed.
<h3>1. Move to the directory where this Readme.html file is located.</h3>
<p>In the description below, we assume that the platform is JDK 1.2
(or later) for Solaris. If the platform is JDK 1.2 (or later) for
Windows, the class-path option is:
<ul><pre>
-classpath ".;javassist.jar"
</pre></ul>
<p>If you don't want to put the class-path option, copy
<tt>./javassist.jar</tt> to
<ul><<i>java-home</i>><tt>/jre/lib/ext/</tt>.</ul>
<p><<i>java-home</i>> depends on the system. It is usually
<tt>/usr/local/java</tt>, <tt>c:\jdk1.2\</tt>, etc.
<p>If you don't use javassist.jar, first compile Javassist:
<ul><pre>
% cd src
% javac -d .. javassist/*.java javassist/*/*.java
% cd ..
</pre></ul>
<p>Then you can compile and run the sample programs without the class-path
option.
<h3>2. sample/Test.java</h3>
<p> This is a very simple program using Javassist.
<p> To run, type the commands:
<ul><pre>
% javac -classpath ".:javassist.jar" sample/Test.java
% java -cp ".:javassist.jar" sample.Test
</pre></ul>
<p> For more details, see <a type="text/plain" href="sample/Test.java">sample/Test.java</a>
<h3>3. sample/reflect/*.java</h3>
<p> This is the "verbose metaobject" example well known in reflective
programming. This program dynamically attaches a metaobject to
a Person object. The metaobject prints a message if a method
is called on the Person object.
<p> To run, type the commands:
<ul><pre>
% javac -classpath ".:javassist.jar" sample/reflect/*.java
% java -cp ".:javassist.jar" javassist.reflect.Loader sample.reflect.Main Joe
</pre></ul>
<p>Compare this result with that of the regular execution without reflection:
<ul><pre>% java -cp ".:javassist.jar" sample.reflect.Person Joe</pre></ul>
<p> For more details, see <a type="text/plain" href="sample/reflect/Main.java">sample/reflect/Main.java</a>
<p> Furthermore, the Person class can be statically modified so that
all the Person objects become reflective without sample.reflect.Main.
To do this, type the commands:
<ul><pre>
% java -cp ".:javassist.jar" javassist.reflect.Compiler sample.reflect.Person -m sample.reflect.VerboseMetaobj
</pre></ul>
<p> Then,
<ul><pre>
% java -cp ".:javassist.jar" sample.reflect.Person Joe
</pre></ul>
<h3>4. sample/duplicate/*.java</h3>
<p> This is another example of reflective programming.
<p> To run, type the commands:
<ul><pre>
% javac -classpath ".:javassist.jar" sample/duplicate/*.java
% java -cp ".:javassist.jar" sample.duplicate.Main
</pre></ul>
<p>Compare this result with that of the regular execution without reflection:
<ul><pre>% java sample.duplicate.Viewer</pre></ul>
<p>For more details, see
<a type="text/plain" href="sample/duplicate/Main.java">sample/duplicate/Main.java</a>
<h3>5. sample/vector/*.java</h3>
<p>This example shows the use of Javassit for producing a class representing
a vector of a given type at compile time.
This is a demonstration of the use of <tt>javassist.preproc</tt> package.
<p> To run, type the commands:
<ul><pre>
% javac -classpath ".:javassist.jar" sample/vector/*.java
% java -cp ".:javassist.jar" javassist.preproc.Compiler sample/vector/Test.j
% javac sample/vector/Test.java
% java sample.vector.Test
</pre></ul>
<p>For more details, see
<a type="text/plain" href="sample/vector/Test.j">sample/vector/Test.j</a>
and <a type="text/plain" href="sample/vector/VectorAssistant.java">sample/vector/VectorAssistant.java</a>
<h3>6. sample/rmi/*.java</h3>
<p> This demonstrates the javassist.rmi package.
<p> To run, type the commands:
<ul><pre>
% javac -classpath ".:javassist.jar" sample/rmi/*.java
% java -cp ".:javassist.jar" sample.rmi.Counter 5001
</pre></ul>
<p> The second line starts a web server listening to port 5001.
<p> Then, open <a href="sample/rmi/webdemo.html">sample/rmi/webdemo.html</a>
with a web browser running
on the local host. (<tt>webdemo.html</tt> trys to fetch an applet from
<tt>http://localhost:5001/</tt>, which is the web server we started above.)
<p> Otherwise, run sample.rmi.CountApplet as an application:
<ul><pre>
% java -cp ".:javassist.jar" javassist.web.Viewer localhost 5001 sample.rmi.CountApplet
</pre></ul>
<h3>7. sample/evolve/*.java</h3>
<p> This is a demonstration of the class evolution mechanism implemented
with Javassist. This mechanism enables a Java program to reload an
existing class file under some restriction.
<p> To run, type the commands:
<ul><pre>
% javac -classpath ".:javassist.jar" sample/evolve/*.java
% java -cp ".:javassist.jar" sample.evolve.DemoLoader 5003
</pre></ul>
<p> The second line starts a class loader DemoLoader, which runs a web
server DemoServer listening to port 5003.
<p> Then, open <a href="http://localhost:5003/demo.html">http://localhost:5003/demo.html</a> with a web browser running
on the local host.
(Or, see <a href="sample/evolve/start.html">sample/evolve/start.html</a>.)
<h3>8. Hints</h3>
<p>Javassist provides a class file viewer for debugging. For more details,
see javassist.Dump.
<p><br>
<h2>Changes</h2>
<p>- version 2.5 in May, 2003.
<br>From this version, Javassist is part of the JBoss project.
<ul>
<li>The license was changed from MPL to MPL/LGPL dual.
<li>ClassPool.removeClassPath() and ClassPath.close() have been added.
<li>ClassPool.makeClass(InputStream) has been added.
<li>javassist.expr.Handler has been added.
<li>CtMethod.isEmpty() and CtConstructor.isEmpty() have been added.
<li>LoaderClassPath has been implemented.
</ul>
<p>- version 2.4 in February, 2003.
<ul>
<li>The compiler included in Javassist did not correctly work with
interface methods. This bug was fixed.
<li>Now javassist.bytecode.Bytecode allows more than 255 local
variables in the same method.
<li>javassist.expr.Instanceof and Cast have been added.
<li>javassist.expr.{MethodCall,NewExpr,FieldAccess,Instanceof,Cast}.where()
have been added. They return the caller-side method surrounding the
expression.
<li>javassist.expr.{MethodCall,NewExpr,FieldAccess,Instanceof,Cast}.mayThrow()
have been added.
<li>$class has been introduced.
<li>The parameters to replaceFieldRead(), replaceFieldWrite(),
and redirectFieldAccess() in javassist.CodeConverter are changed.
<li>The compiler could not correctly handle a try-catch statement.
This bug has been fixed.
</ul>
<p>- version 2.3 in December, 2002.
<ul>
<li>The tutorial has been revised a bit.
<li>SerialVersionUID class was donated by Bob Lee. Thanks.
<li>CtMethod.setBody() and CtConstructor.setBody() have been added.
<li>javassist.reflect.ClassMetaobject.useContextClassLoader has been added.
If true, the reflection package does not use Class.forName() but uses
a context class loader specified by the user.
<li>$sig and $type are now available.
<li>Bugs in Bytecode.write() and read() have been fixed.
</ul>
<p>- version 2.2 in October, 2002.
<ul>
<li>The tutorial has been revised.
<li>A new package <code>javassist.expr</code> has been added.
This is replacement of classic <code>CodeConverter</code>.
<li>javassist.ConstParameter was changed into
javassist.CtMethod.ConstParameter.
<li>javassist.FieldInitializer was renamed into
javassist.CtField.Initializer.
<li>A bug in javassist.bytecode.Bytecode.addInvokeinterface() has been
fixed.
<li>In javassist.bytecode.Bytecode, addGetfield(), addGetstatic(),
addInvokespecial(), addInvokestatic(), addInvokevirtual(),
and addInvokeinterface()
have been modified to update the current statck depth.
</ul>
<p>- version 2.1 in July, 2002.
<ul>
<li>javassist.CtMember and javassist.CtBehavior have been added.
<li>javassist.CtClass.toBytecode() has been added.
<li>javassist.CtClass.toClass() and javassist.ClassPool.writeAsClass()
has been added.
<li>javassist.ByteArrayClassPath has been added.
<li>javassist.bytecode.Mnemonic has been added.
<li>Several bugs have been fixed.
</ul>
<p>- version 2.0 (major update) in November, 2001.
<ul>
<li>The javassist.bytecode package has been provided. It is a
lower-level API for directly modifying a class file although
the users must have detailed knowledge of the Java bytecode.
<li>The mechanism for creating CtClass objects have been changed.
<li>javassist.tool.Dump moves to the javassist package.
</ul>
<p>version 1.0 in July, 2001.
<ul>
<li>javassist.reflect.Metaobject and ClassMetaobject was changed.
Now they throw the same exception that they receive from a
base-level object.
</ul>
<p>- version 0.8
<ul>
<li>javassist.tool.Dump was added. It is a class file viewer.
<li>javassist.FiledInitializer.byNewArray() was added. It is for
initializing a field with an array object.
<li>javassist.CodeConverter.redirectMethodCall() was added.
<li>javassist.Run was added.
</ul>
<p>- version 0.7
<ul>
<li>javassit.Loader was largely modified. javassist.UserLoader was
deleted. Instead, Codebase was renamed to ClassPath
and UserClassPath was added. Now programmers who want to
customize Loader must write a class implementing UserClassPath
instead of UserLoader. This change is for sharing class search paths
between Loader and CtClass.CtClass(String).
<li>CtClass.addField(), addMethod(), addConstructor(), addWrapper() were
also largely modified so that it receives CtNewMethod, CtNewConstructor,
or CtNewField. The static methods for creating these objects were
added to the API.
<li>Constructors are now represented by CtConstructor objects.
CtConstructor is a subclass of CtMethod.
<li>CtClass.getUserAttribute() was removed. Use CtClass.getAttribute().
<li>javassist.rmi.RmiLoader was added.
<li>javassist.reflect.Metalevel._setMetaobject() was added. Now
metaobjects can be replaced at runtime.
</ul>
<p>- version 0.6
<ul>
<li>Javassist was modified to correctly deal with array types appearing
in signatures.
<li>A bug crashed resulting bytecode if a class includes a private static
filed. It has been fixed.
<li>javassist.CtNewInterface was added.
<li>javassist.Loader.recordClass() was renamed into makeClass().
<li>javassist.UserLoader.loadClass() was changed to take the second
parameter.
</ul>
<p>- version 0.5
<ul>
<li>a bug-fix version.
</ul>
<p>- version 0.4
<ul>
<li>Major update again. Many classes and methods were changed.
Most of methods taking java.lang.Class have been changed to
take javassist.CtClass.
</ul>
<p>- version 0.3
<ul>
<li>Major update. Many classes and methods were changed.
</ul>
<p>- version 0.2
<ul>
<li>Jar/zip files are supported.
</ul>
<p>-version 0.1 in April, 1999.
<ul>
<li>The first release.
</ul>
<p><br>
<h2>Bug reports etc.</h2>
<dl>
<dt>Bug reports:
<dd><tt><a href="mailto:chiba@acm.org">chiba@acm.org</a></tt>
<br>or
<tt><a href="mailto:chiba@is.titech.ac.jp">chiba@is.titech.ac.jp</a></tt>
<br>
<p><dt>The home page of Javassist:
<dd>Visit <a href="http://www.jboss.org/index.html?module=html&op=userdisplay&id=developers/projects/javassist"><tt>www.jboss.org</tt></a>
</dl>
<p><br>
<a name="copyright">
<h2>Copyright notices</h2>
<p>Javassist, a Java-bytecode translator toolkit.
<br>Copyright (C) 1999-2003 Shigeru Chiba. All Rights Reserved.
<p>The contents of this software, Javassist, are subject to
the Mozilla Public License Version 1.1 (the "License");<br>
you may not use this software except in compliance
with the License. You may obtain a copy of the License at
<br>http://www.mozilla.org/MPL/
<p>Software distributed under the License is distributed on an "AS IS"
basis, WITHOUT WARRANTY OF <br>ANY KIND, either express or implied.
See the License for the specific language governing rights and
<br>limitations under the License.
<p>The Original Code is Javassist.
<p>The Initial Developer of the Original Code is Shigeru Chiba.
Portions created by the Initial Developer are<br>
Copyright (C) 1999-2003 Shigeru Chiba. All Rights Reserved.
<p>Contributor(s): ______________________________________.
<p>Alternatively, the contents of this software may be used under the
terms of the GNU Lesser General Public License Version 2.1 or later
(the "LGPL"), in which case the provisions of the LGPL are applicable
instead of those above. If you wish to allow use of your version of
this software only under the terms of the LGPL, and not to allow others to
use your version of this software under the terms of the MPL, indicate
your decision by deleting the provisions above and replace them with
the notice and other provisions required by the LGPL. If you do not
delete the provisions above, a recipient may use your version of this
software under the terms of either the MPL or the LGPL.
<p>If you obtain this software as part of JBoss, the contents of this
software may be used under only the terms of the LGPL. To use them
under the MPL, you must obtain a separate package including only
Javassist but not the other part of JBoss.
<p><br>
<h2>Acknowledgments</h2>
<p>The development of this software is sponsored in part by the PRESTO
programs of <a href="http://www.jst.go.jp/">Japan
Science and Technology Corporation</a>.
<p>I'd like to thank Michiaki Tatsubori, Johan Cloetens,
Philip Tomlinson, Alex Villazon, Pascal Rapicault, Dan HE, Eric Tanter,
Michael Haupt, Toshiyuki Sasaki, Renaud Pawlak, Luc Bourlier,
Eric Bui, Lewis Stiller, Susumu Yamazaki, Rodrigo Teruo Tomita,
Marc Segura-Devillechaise, Jan Baudisch, Julien Blass, Yoshiki Sato,
Fabian Crabus, Bo Norregaard Jorgensen, Bob Lee, Bill Burke,
Remy Sanlaville, Muga Nishizawa, Alexey Loubyansky, Saori Oki,
Andreas Salathe, Dante Torres estrada, S. Pam, Nuno Santos,
Denis Taye, and Colin Sampaleanu
for their contributions.
<p><br>
<hr>
<a href="http://www.is.titech.ac.jp/~chiba">Shigeru Chiba</a>
(Email: <tt>chiba@acm.org</tt>)
<br>Dept. of Math. and Computing Sciences,
<a href="http://www.titech.ac.jp">Tokyo Institute of Technology</a>
|
