Can't compile javascript using ant and closure compiler because of Jquery's $ is undeclared

I am trying to get Google Closure Compiler to work to compile my javascript code that uses Jquery but i keep getting variable $ is undeclared is there a way to get it to see the $ variable. Is there a way for closure Compiler to see the Jquery library but not compile it. here is my ant script

<?xml version="1.0"?>
<project basedir="." default="compile">

<taskdef name="jscomp" classname="com.google.javascript.jscomp.ant.CompileTask"
       classpath="build/compiler.jar"/>

<target name="compile">

<jscomp compilationLevel="simple" warning="verbose" 
        debug="false" output="output/file.js">

  <sources dir="${basedir}/src">
    <file name="js.js"/><!-- the file I'm trying to compile -->
  </sources>

</jscomp>

</target>

</project>

My Jquery library is called min.js and its in the src folder with js.js

I'm sure this is a easy question but I'm just missing something. Thanks in advance!

You need to include the jQuery externs. Each major version of jQuery has its own extern file. You can find them at http://code.google.com/p/closure-compiler/source/browse/#svn%2Ftrunk%2Fcontrib%2Fexterns

Once you've downloaded the appropriate extern, here's how you would reference it while compiling:

<?xml version="1.0"?>
<project basedir="." default="compile">

<taskdef name="jscomp" classname="com.google.javascript.jscomp.ant.CompileTask"
       classpath="build/compiler.jar"/>

<target name="compile">

<jscomp compilationLevel="simple" warning="verbose" 
    debug="false" output="output/file.js">

  <sources dir="${basedir}/src">
    <file name="js.js"/><!-- the file I'm trying to compile -->
  </sources>

  <externs dir="${basedir}/src">
    <file name="jquery-1.7.js"/>
  </externs>
</jscomp>

</target>