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<title>javac - The Java Compiler</title>
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<h1>javac - The Java Compiler</h1>
<blockquote>
<b>javac</b> compiles Java programs.
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<h2>SYNOPSIS</h2>
<blockquote>
<pre>
javac [ <a href="javac.html#Options">options</a> ] filename.java ...
javac_g [ <a href="javac.html#Options">options</a> ] filename.java ...
</pre>
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<h2>DESCRIPTION</h2>
<blockquote>
The <b>javac</b> command compiles Java source code into Java bytecodes.
You then use the Java interpreter - the <a href="java.html"><b>java</b></a>
command - to interprete the Java bytecodes.
<p>
Java source code must be contained in files whose filenames end in the
<i>.java</i> extension. For every class defined in the source files passed
to <b>javac</b>, the compiler stores the resulting bytecodes in a file named
<i>classname.class</i>. The compiler places the resulting <i>.class</i>
files in the same directory as the corresponding <i>.java</i> file (unless
you specify the <i>-d</i> option).
<p>
When you define your own classes you need to specify their location.
Use CLASSPATH to do this. CLASSPATH consists of a colon separated list of
directories that specifies the path. If the source files passed to <b>javac</b>
references a class not defined in any of the files passed to <b>javac</b>
then <b>javac</b> searches for the referenced class using the class path.
For example:
<blockquote>
<pre>
:/home/avh/classes
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</blockquote>
Note that the system always appends the location of the system classes
onto the end of the class path unless you use the <i>-classpath</i> option to
specify a path.
<p>
<b>javac_g</b> is a non-optimized version of <b>javac</b> suitable for
use with debuggers like <a href=jdb.html><b>jdb</b></a>.
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<a name=Options>
<h2>OPTIONS</h2>
</a>
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<dl>
<dt><b>-classpath path</b>
<dd>
Specifies the path <b>javac</b> uses to look up classes. Overrides the default
or the CLASSPATH environment variable if it is set. Directories are separated by
colons. Thus the general format for <i>path</i> is:
<blockquote>
<pre>
:<your_path>
</pre>
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For example:
<blockquote>
<pre>
:/home/avh/classes:/usr/local/java/classes
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<p>
<dt><b>-d directory</b>
<dd>
Specifies the root directory of the class hierarchy. Thus doing:
<blockquote>
<pre>
javac -d <my_dir>/editor/gui/TextWindow.java
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causes the class file for the class called editor.gui.Textwindow to be
saved as:
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<pre>
<my_dir>/editor/gui/TextWindow.class
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<p>
<dt><b>-g</b>
<dd>
Enables generation of debugging tables. Debugging tables contain
information about line numbers and local variables - information used
by debugging tools. By default, only line numbers are generated, unless
optimization (<i>-O</i>) is turned on.
<p>
<dt><b>-nowarn</b>
<dd>
Turns off warnings. If used the compiler does not print out any warnings.
<p>
<dt><b>-O</b>
<dd>
Optimizes compiled code by inlining static, final and private methods.
Note that your classes may get larger in size.
<p>
<dt><b>-verbose</b>
<dd>
Causes the compiler and linker to print out messages about what source
files are being compiled and what class files are being loaded.
</dl>
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<h2>ENVIRONMENT VARIABLES</h2>
<blockquote>
<dl>
<dt><b>CLASSPATH</b>
<dd>
Used to provide the system a path to user-defined classes. Directories are
separated by colons, for example,
<blockquote>
<pre>
:/home/avh/classes:/usr/local/java/classes
</pre>
</blockquote>
</dl>
</blockquote>
<h2>SEE ALSO</h2>
<blockquote>
<a href="java.html">java</a>,
<a href="jdb.html">jdb</a>,
<a href="javah.html">javah</a>,
<a href="javap.html">javap</a>,
<a href="javadoc.html">javadoc</a>,
<a href="../javaspec/javaspec_1.html">The Java Language Specification</a>
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