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Java source and .class files, producing .class files compliant with any
Java VM (1.1 or later). It combines compilation and bytecode weaving
and supports incremental builds; you can also weave bytecode
at run-time using <a class="xref" href="ltw.html" title="Chapter 5. Load-Time Weaving">Load-Time Weaving</a>.
</p><p> The arguments after the options specify the source file(s) to compile.
To specify source classes, use <em class="parameter"><code>-inpath</code></em> (below).
Files may be listed directly on the command line or in a file.
The <em class="parameter"><code>-argfile <em class="replaceable"><code>file</code></em></code></em>
and <em class="parameter"><code>@<em class="replaceable"><code>file</code></em></code></em> forms
are equivalent, and are interpreted as meaning all the arguments
listed in the specified file.
</p><p>
<span class="command"><strong>Note:</strong></span>
You must explicitly pass <span class="command"><strong>ajc</strong></span> all necessary sources.
Be sure to include the source not only for the
aspects or pointcuts but also for any affected types.
Specifying all sources is necessary because, unlike javac, ajc does not
search the sourcepath for classes.
(For a discussion of what affected types might be required,
see <a class="ulink" href="../progguide/implementation.html" target="_top">The AspectJ
Programming Guide, Implementation Appendix</a>.)
</p><p>
To specify sources, you can list source files as arguments or use the
options <em class="parameter"><code>-sourceroots</code></em> or <em class="parameter"><code>-inpath</code></em>.
If there are multiple sources for any type, the result is undefined
since ajc has no way to determine which source is correct. (This
happens most often when users include the destination directory
on the inpath and rebuild.)
</p><div class="refsect2"><a name="ajc_options"></a><h3>Options</h3><div class="variablelist"><dl class="variablelist"><dt><span class="term">-injars <em class="replaceable"><code>JarList</code></em></span></dt><dd><p>
deprecated: since 1.2, use -inpath, which also takes
directories.
</p></dd><dt><span class="term">-inpath <em class="replaceable"><code>Path</code></em></span></dt><dd><p>
Accept as source bytecode any .class files in the
.jar files or directories on Path.
The output will include these
classes, possibly as woven with any applicable aspects.
Path is a single argument containing
a list of paths to zip files or directories,
delimited by the platform-specific path delimiter.
</p></dd><dt><span class="term">-aspectpath <em class="replaceable"><code>Path</code></em></span></dt><dd><p>
Weave binary aspects from jar files and directories on path into all sources.
The aspects should have been output by the same version
of the compiler.
When running the output classes, the run classpath should contain
all aspectpath entries.
Path, like classpath, is a single argument containing
a list of paths to jar files, delimited by the platform-
specific classpath delimiter.
</p></dd><dt><span class="term">-argfile <em class="replaceable"><code>File</code></em></span></dt><dd><p>
The file contains a line-delimited list of arguments.
Each line in the file should contain one option, filename, or
argument string (e.g., a classpath or inpath).
Arguments read from the file are inserted into the argument list
for the command. Relative paths in the file are calculated from
the directory containing the file (not the current working directory).
Comments, as in Java, start with <code class="literal">//</code> and
extend to the end of the line. Options specified in argument
files may override rather than extending existing option values,
so avoid specifying options like <em class="replaceable"><code>-classpath</code></em>
in argument files unlike the argument file is the only build
specification. The form <em class="replaceable"><code>@file</code></em> is the same
as specifying <em class="replaceable"><code>-argfile file</code></em>.
</p></dd><dt><span class="term">-outjar <em class="replaceable"><code>output.jar</code></em></span></dt><dd><p>Put output classes in zip file output.jar.
</p></dd><dt><span class="term">-outxml</span></dt><dd><p>Generate aop.xml file for load-time weaving with default name.
</p></dd><dt><span class="term">-outxmlfile <em class="replaceable"><code>custom/aop.xml</code></em></span></dt><dd><p>Generate aop.xml file for load-time weaving with custom name.
</p></dd><dt><span class="term">-incremental</span></dt><dd><p>Run the compiler continuously.
After the initial compilation, the compiler will
wait to recompile until it reads a newline from the standard
input, and will quit when it reads a 'q'.
It will only recompile necessary components, so a recompile
should be much faster than doing a second compile.
This requires -sourceroots.
</p></dd><dt><span class="term">-sourceroots <em class="replaceable"><code>DirPaths</code></em></span></dt><dd><p>Find and build all .java or .aj source files under
any directory listed in DirPaths.
DirPaths, like classpath, is a single argument containing
a list of paths to directories, delimited by the platform-
specific classpath delimiter.
Required by -incremental.
</p></dd><dt><span class="term">-crossrefs</span></dt><dd><p>
Generate a build .ajsym file into the output directory. Used for
viewing crosscutting references by tools like the AspectJ
Browser.
</p></dd><dt><span class="term">-emacssym</span></dt><dd><p>
Generate .ajesym symbol files for emacs support (deprecated).
</p></dd><dt><span class="term">-Xlint</span></dt><dd><p>Same as -Xlint:warning (enabled by default)
</p></dd><dt><span class="term">-Xlint:{level}</span></dt><dd><p>Set default level for messages about potential
programming mistakes in crosscutting code.
{level} may be ignore, warning, or error.
This overrides entries in
org/aspectj/weaver/XlintDefault.properties
from aspectjtools.jar, but does not override levels set
using the -Xlintfile option.
</p></dd><dt><span class="term">-Xlintfile <em class="replaceable"><code>PropertyFile</code></em></span></dt><dd><p>Specify properties file to set levels for
specific crosscutting messages.
PropertyFile is a path to a Java .properties file that
takes the same property names and values as
org/aspectj/weaver/XlintDefault.properties
from aspectjtools.jar, which it also overrides.
</p></dd><dt><span class="term">-help</span></dt><dd><p>
Emit information on compiler options and usage
</p></dd><dt><span class="term">-version</span></dt><dd><p>
Emit the version of the AspectJ compiler
</p></dd><dt><span class="term">-classpath <em class="replaceable"><code>Path</code></em></span></dt><dd><p>
Specify where to find user class files.
Path is a single argument containing
a list of paths to zip files or directories,
delimited by the platform-specific path delimiter.
</p></dd><dt><span class="term">-bootclasspath <em class="replaceable"><code>Path</code></em></span></dt><dd><p>
Override location of VM's bootclasspath
for purposes of evaluating types when compiling.
Path is a single argument containing
a list of paths to zip files or directories,
delimited by the platform-specific path delimiter.
</p></dd><dt><span class="term">-extdirs <em class="replaceable"><code>Path</code></em></span></dt><dd><p>
Override location of VM's extension directories
for purposes of evaluating types when compiling.
Path is a single argument containing
a list of paths to directories,
delimited by the platform-specific path delimiter.
</p></dd><dt><span class="term">-d <em class="replaceable"><code>Directory</code></em></span></dt><dd><p>
Specify where to place generated .class files.
If not specified, <em class="replaceable"><code>Directory</code></em>
defaults to the current working dir.
</p></dd><dt><span class="term">-target <em class="replaceable"><code>[1.1 to 1.5]</code></em></span></dt><dd><p>Specify classfile target setting (1.1 to 1.5, default is 1.2)
</p></dd><dt><span class="term">-1.3</span></dt><dd><p>Set compliance level to 1.3
This implies -source 1.3 and -target 1.1.
</p></dd><dt><span class="term">-1.4</span></dt><dd><p>Set compliance level to 1.4 (default)
This implies -source 1.4 and -target 1.2.
</p></dd><dt><span class="term">-1.5</span></dt><dd><p>Set compliance level to 1.5.
This implies -source 1.5 and -target 1.5.
</p></dd><dt><span class="term">-source <em class="replaceable"><code>[1.3|1.4|1.5]</code></em></span></dt><dd><p>Toggle assertions (1.3, 1.4, or 1.5 - default is 1.4).
When using -source 1.3, an assert() statement valid under
Java 1.4 will result in a compiler error.
When using -source 1.4,
treat <code class="literal">assert</code> as a keyword and
implement assertions according to the 1.4 language spec.
When using -source 1.5,
Java 5 language features are permitted.
</p></dd><dt><span class="term">-nowarn</span></dt><dd><p>Emit no warnings (equivalent to '-warn:none')
This does not suppress messages
generated by <code class="literal">declare warning</code> or
<code class="literal">Xlint</code>.
</p></dd><dt><span class="term">-warn: <em class="replaceable"><code>items</code></em></span></dt><dd><p>Emit warnings for any instances of
the comma-delimited list of questionable code
(eg '-warn:unusedLocals,deprecation'):
</p><pre class="programlisting">
constructorName method with constructor name
packageDefaultMethod attempt to override package-default method
deprecation usage of deprecated type or member
maskedCatchBlocks hidden catch block
unusedLocals local variable never read
unusedArguments method argument never read
unusedImports import statement not used by code in file
none suppress all compiler warnings
</pre><p>
<code class="literal">-warn:none</code> does not suppress messages
generated by <code class="literal">declare warning</code> or
<code class="literal">Xlint</code>.
</p></dd><dt><span class="term">-deprecation</span></dt><dd><p>Same as -warn:deprecation
</p></dd><dt><span class="term">-noImportError</span></dt><dd><p>Emit no errors for unresolved imports
</p></dd><dt><span class="term">-proceedOnError</span></dt><dd><p>Keep compiling after error,
dumping class files with problem methods
</p></dd><dt><span class="term">-g<em class="replaceable"><code>:[lines,vars,source]</code></em></span></dt><dd><p>debug attributes level, that may take three forms:
</p><pre class="programlisting">
-g all debug info ('-g:lines,vars,source')
-g:none no debug info
-g:{items} debug info for any/all of [lines, vars, source], e.g.,
-g:lines,source
</pre><p>
</p></dd><dt><span class="term">-preserveAllLocals</span></dt><dd><p>Preserve all local variables during code generation
(to facilitate debugging).
</p></dd><dt><span class="term">-referenceInfo</span></dt><dd><p>Compute reference information.
</p></dd><dt><span class="term">-encoding <em class="replaceable"><code>format</code></em></span></dt><dd><p>Specify default source encoding format.
Specify custom encoding on a per file basis by suffixing
each input source file/folder name with '[encoding]'.
</p></dd><dt><span class="term">-verbose</span></dt><dd><p>Emit messages about accessed/processed compilation units
</p></dd><dt><span class="term">-showWeaveInfo</span></dt><dd><p>Emit messages about weaving
</p></dd><dt><span class="term">-log <em class="replaceable"><code>file</code></em></span></dt><dd><p>Specify a log file for compiler messages.
</p></dd><dt><span class="term">-progress</span></dt><dd><p>Show progress (requires -log mode).
</p></dd><dt><span class="term">-time</span></dt><dd><p>Display speed information.
</p></dd><dt><span class="term">-noExit</span></dt><dd><p>Do not call System.exit(n) at end of compilation
(n=0 if no error)
</p></dd><dt><span class="term">-repeat <em class="replaceable"><code>N</code></em></span></dt><dd><p>Repeat compilation process N times
(typically to do performance analysis).
</p></dd><dt><span class="term">-XterminateAfterCompilation</span></dt><dd><p>Causes compiler to terminate before weaving
</p></dd><dt><span class="term">-XaddSerialVersionUID</span></dt><dd><p>Causes the compiler to calculate and add
the SerialVersionUID field to any type implementing
Serializable that is affected by an aspect. The field
is calculated based on the class before weaving has
taken place.
</p></dd><dt><span class="term">-Xreweavable[:compress]</span></dt><dd><p>(Experimental - deprecated as now default)
Runs weaver in reweavable mode which causes
it to create woven classes that can be rewoven, subject to the restriction that
on attempting a reweave all the types that advised the woven type must be accessible.
</p></dd><dt><span class="term">-XnoInline</span></dt><dd><p>(Experimental) do not inline around advice
</p></dd><dt><span class="term">-XincrementalFile <em class="replaceable"><code>file</code></em></span></dt><dd><p>(Experimental) This works like incremental mode,
but using a file rather than standard input to control the compiler.
It will recompile each time file is changed and
and halt when file is deleted.
</p></dd><dt><span class="term">-XserializableAspects</span></dt><dd><p>
(Experimental) Normally it is an error to declare
aspects Serializable. This option removes that restriction.
</p></dd><dt><span class="term">-XnotReweavable</span></dt><dd><p>
(Experimental) Create class files that can't be subsequently rewoven by AspectJ.
</p></dd><dt><span class="term">-Xajruntimelevel:1.2, ajruntimelevel:1.5</span></dt><dd><p>
(Experimental) Allows code to be generated that targets a 1.2 or a 1.5 level AspectJ runtime (default 1.5)
</p></dd></dl></div></div><div class="refsect2"><a name="idp61521248"></a><h3>File names</h3><p>ajc accepts source files with either the <code class="filename">.java</code>
extension or the <code class="filename">.aj</code> extension. We normally use
<code class="filename">.java</code> for all of our files in an AspectJ system -- files
that contain aspects as well as files that contain classes. However, if
you have a need to mechanically distinguish files that use AspectJ's
additional functionality from those that are pure Java we recommend using
the <code class="filename">.aj</code> extension for those files.</p><p>We'd like to discourage other means of mechanical distinction such as
naming conventions or sub-packages in favor of the <code class="filename">.aj</code>
extension.</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>Filename conventions are hard to enforce and lead to awkward names
for your aspects. Instead of <code class="filename">TracingAspect.java</code> we
recommend using <code class="filename">Tracing.aj</code> (or just
<code class="filename">Tracing.java</code>) instead.</p></li><li class="listitem"><p>Sub-packages move aspects out of their natural place in a system
and can create an artificial need for privileged aspects. Instead of
adding a sub-package like <code class="filename">aspects</code> we recommend using the
<code class="filename">.aj</code> extension and including these files in your existing
packages instead.</p></li></ul></div></div><div class="refsect2"><a name="idp61531168"></a><h3>Compatibility</h3><p>
AspectJ is a compatible extension to the Java programming language. The
AspectJ compiler adheres to the <a class="ulink" href="http://java.sun.com/docs/books/jls/index.html" target="_top"> <em class="citetitle">The Java Language Specfication, Second
Edition</em></a> and to the <a class="ulink" href="http://java.sun.com/docs/books/vmspec/index.html" target="_top"><em class="citetitle">The Java Virtual Machine Specification, Second
Edition</em></a> and runs on any Java 2 compatible
platform. The code it generates runs on any Java 1.1 or later
compatible platform.
For more information on compatibility with
Java and with previous releases of AspectJ,
see
<a class="xref" href="compatibility.html#versionCompatibility" title="Version Compatibility">AspectJ Version Compatibility</a>.
</p></div><div class="refsect2"><a name="idp61535424"></a><h3>Examples</h3><div class="example"><a name="simpleexample"></a><p class="title"><b>Example 2.1. A simple example</b></p><div class="example-contents"><p>Compile two files:</p><pre class="programlisting">
ajc HelloWorld.java Trace.java
</pre></div></div><br class="example-break"><div class="example"><a name="exampleusingargfile"></a><p class="title"><b>Example 2.2. An example using -argfile/@</b></p><div class="example-contents"><p>
To avoid specifying file names on the command line,
list source files in a line-delimited text argfile.
Source file paths may be absolute or relative to the argfile,
and may include other argfiles by @-reference.
The following file <code class="literal">sources.lst</code>
contains absolute and relative files and @-references:
</p><pre class="programlisting">
Gui.java
/home/user/src/Library.java
data/Repository.java
data/Access.java
@../../common/common.lst
@/home/user/src/lib.lst
view/body/ArrayView.java</pre><p>Compile the files using either the -argfile or @ form:</p><pre class="programlisting">
ajc -argfile sources.lst
ajc @sources.lst</pre><p>
Argfiles are also supported by jikes and javac, so you
can use the files in hybrid builds. However, the support varies:
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>Only ajc accepts command-line options</p></li><li class="listitem"><p>Jikes and Javac do not accept internal @argfile references.
</p></li><li class="listitem"><p>Jikes and Javac only accept the @file form on the command line.</p></li></ul></div></div></div><br class="example-break"><div class="example"><a name="examplebytecode"></a><p class="title"><b>Example 2.3. An example using -inpath and -aspectpath</b></p><div class="example-contents"><p>Bytecode weaving using -inpath:
AspectJ 1.2 supports weaving .class files in input zip/jar files
and directories.
Using input jars is like compiling the corresponding
source files, and all binaries are emitted to output. Although
Java-compliant compilers may differ in their output, ajc should
take as input any class files produced by javac, jikes, eclipse,
and, of course, ajc. Aspects included in -inpath will be woven into
like other .class files, and they will affect other types as usual.
</p><p>Aspect libraries using -aspectpath:
AspectJ 1.1 supports weaving from read-only libraries containing
aspects. Like input jars, they affect all input; unlike input
jars, they themselves are not affected or emitted as output.
Sources compiled with aspect libraries must be run with the same
aspect libraries on their classpath.
</p><p>The following example builds the tracing example in a
command-line environment; it creates a read-only aspect library,
compiles some classes for use as input bytecode, and
compiles the classes and other sources with the aspect library.
</p><p>The tracing example is in the AspectJ distribution
({aspectj}/doc/examples/tracing). This uses the following files:
</p><pre class="programlisting">
aspectj1.1/
bin/
ajc
lib/
aspectjrt.jar
examples/
tracing/
Circle.java
ExampleMain.java
lib/
AbstractTrace.java
TraceMyClasses.java
notrace.lst
Square.java
tracelib.lst
tracev3.lst
TwoDShape.java
version3/
Trace.java
TraceMyClasses.java
</pre><p>Below, the path separator is taken as ";", but file separators
are "/". All commands are on one line. Adjust paths and
commands to your environment as needed.
</p><p>Setup the path, classpath, and current directory:</p><pre class="programlisting">
cd examples
export ajrt=../lib/aspectjrt.jar
export CLASSPATH="$ajrt"
export PATH="../bin:$PATH"
</pre><p>Build a read-only tracing library:</p><pre class="programlisting">
ajc -argfile tracing/tracelib.lst -outjar tracelib.jar
</pre><p>Build the application with tracing in one step:</p><pre class="programlisting">
ajc -aspectpath tracelib.jar -argfile tracing/notrace.lst -outjar tracedapp.jar
</pre><p>Run the application with tracing:</p><pre class="programlisting">
java -classpath "$ajrt;tracedapp.jar;tracelib.jar" tracing.ExampleMain
</pre><p>Build the application with tracing from binaries in two steps:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
(a) Build the application classes (using javac for demonstration's sake):</p><pre class="programlisting">
mkdir classes
javac -d classes tracing/*.java
jar cfM app.jar -C classes .
</pre></li><li class="listitem"><p>
(b) Build the application with tracing:</p><pre class="programlisting">
ajc -inpath app.jar -aspectpath tracelib.jar -outjar tracedapp.jar
</pre></li></ul></div><p>Run the application with tracing (same as above):</p><pre class="programlisting">
java -classpath "$ajrt;tracedapp.jar;tracelib.jar" tracing.ExampleMain
</pre><p>Run the application without tracing:</p><pre class="programlisting">
java -classpath "app.jar" tracing.ExampleMain
</pre></div></div><br class="example-break"></div><div class="refsect2"><a name="idp61560704"></a><h3>The AspectJ compiler API</h3><p>The AspectJ compiler is implemented completely in Java and can be
called as a Java class. The only interface that should be considered
public are the public methods in <code class="literal">org.aspectj.tools.ajc.Main</code>.
E.g., <code class="literal">main(String[] args)</code> takes the
the standard <span class="command"><strong>ajc</strong></span> command line arguments.
This means that an alternative way to run the
compiler is </p><div class="cmdsynopsis"><p><code class="command"><code class="literal">java org.aspectj.tools.ajc.Main</code></code> [<em class="replaceable"><code>option...</code></em>] [<em class="replaceable"><code>file...</code></em>]</p></div><p>To access compiler messages programmatically, use the methods
<code class="literal">setHolder(IMessageHolder holder)</code> and/or
<code class="literal">run(String[] args, IMessageHolder holder)</code>.
<code class="literal">ajc</code> reports each message to the holder
using <code class="literal">IMessageHolder.handleMessage(..)</code>.
If you just want to collect the messages, use
<code class="literal">MessageHandler</code> as your
<code class="literal">IMessageHolder</code>.
For example, compile and run the following with
<code class="literal">aspectjtools.jar</code> on the classpath:
</p><pre class="programlisting">
import org.aspectj.bridge.*;
import org.aspectj.tools.ajc.Main;
import java.util.Arrays;
public class WrapAjc {
public static void main(String[] args) {
Main compiler = new Main();
MessageHandler m = new MessageHandler();
compiler.run(args, m);
IMessage[] ms = m.getMessages(null, true);
System.out.println("messages: " + Arrays.asList(ms));
}
}
</pre></div><div class="refsect2"><a name="idp61573664"></a><h3>Stack Traces and the SourceFile attribute</h3><p>Unlike traditional java compilers, the AspectJ compiler may in
certain cases generate classfiles from multiple source files.
Unfortunately, the original Java class file format does not support
multiple
SourceFile attributes. In order to make sure all source file
information is available, the AspectJ compiler may in some cases
encode multiple filenames in the SourceFile attribute.
When the Java VM generates stack traces, it uses this attribute
to specify the source file.
</p><p>(The AspectJ 1.0 compiler also supports the .class file extensions of JSR-45.
These permit compliant debuggers (such as jdb in Java 1.4.1) to identify
the right file and line even given many source files for a single class.
JSR-45 support is planned for ajc in AspectJ 1.1, but is not in the initial
release. To get fully debuggable .class files, use the -XnoInline option.)
</p><p>Probably the only time you may see this format is when you view
stack traces, where you may encounter traces of the format
</p><pre class="programlisting">
java.lang.NullPointerException
at Main.new$constructor_call37(Main.java;SynchAspect.java[1k]:1030)
</pre><p>where instead of the usual
</p><pre class="programlisting">
File:LineNumber
</pre><p>format, you see
</p><pre class="programlisting">
File0;File1[Number1];File2[Number2] ... :LineNumber
</pre><p>In this case, LineNumber is the usual offset in lines plus the
"start line" of the actual source file. That means you use LineNumber
both to identify the source file and to find the line at issue.
The number in [brackets] after each file tells you the
virtual "start line" for that file (the first file has a start of 0).
</p><p> In our example from the null pointer exception trace,
the virtual start line is 1030. Since the file SynchAspect.java
"starts" at line 1000 [1k], the LineNumber points to line 30 of
SynchAspect.java.
</p><p> So, when faced with such stack traces, the way to find the actual
source location is to look through the list of "start line" numbers to
find the one just under the shown line number. That is the file where
the source location can actually be found. Then, subtract that "start
line" from the shown line number to find the actual line number within
that file.
</p><p>In a class file that comes from only a single source file, the AspectJ
compiler generates SourceFile attributes consistent with
traditional Java compilers.
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