plugin.xml

<?xml version="1.0" encoding="UTF-8"?>
<?eclipse version="3.2"?>
<plugin>
   <extension
       point="org.eclipse.jdt.core.classpathContainerInitializer">
      <classpathContainerInitializer
          id="org.container.directory.SIMPLE_DIR_CONTAINER"
          class="org.container.directory.SimpleDirContainerInitializer"/>
   </extension>
   
   <extension 
       point="org.eclipse.jdt.ui.classpathContainerPage">
      <classpathContainerPage
          id="org.container.directory.SIMPLE_DIR_CONTAINER"
          name="Directory Container"
          class="org.container.directory.SimpleDirContainerPage"/>
   </extension>
   
   <extension
         point="org.eclipse.jdt.ui.javaElementFilters">
         <filter
               id="org.container.directory.ContainerDirFilter"
               targetId="org.eclipse.jdt.ui.PackageExplorer"
               enabled="true"
               name="Classpath Directory Container"
               description="Dynamically include jar files from this directory in the classpath"
               class="org.container.directory.ContainerDirFilter"/>
   </extension>
</plugin>