Find a class or resource on the supplied classpath, or the system classpath if none is supplied. The named property is set if the item can be found. For example:
<whichresource resource="/log4j.properties" property="log4j.url" >
| Attribute | Description | Required | 
| property | The property to fill with the URL of the resource of class. | Yes | 
| class | The name of the class to look for. | Exactly one of these. | 
| resource | The name of the resource to look for. | |
| classpath | The classpath to use when looking up classorresource. | No | 
| classpathref | The classpath to use, given as a reference to a path defined elsewhere. Since Apache Ant 1.7.1. | No | 
      Whichresource's classpath attribute is a
      path-like structure and can also be
      set via a nested <classpath> element.
    
The following shows using a classpath reference.
  <path id="bsf.classpath">
    <fileset dir="${user.home}/lang/bsf" includes="*.jar"/>
  </path>
  <whichresource property="bsf.class.location"
                 class="org.apache.bsf.BSFManager"
                 classpathref="bsf.classpath"/>
  <echo>${bsf.class.location}</echo>
The following shows using a nested classpath.
  <whichresource
    property="ant-contrib.antlib.location"
    resource="net/sf/antcontrib/antlib.xml">
    <classpath>
      <path path="f:/testing/ant-contrib/target/ant-contrib.jar"/>
    </classpath>
  </whichresource>
  <echo>${ant-contrib.antlib.location}</echo>