​<rich:tree var="item">
​   <rich:treeModelRecursiveAdaptor roots="#{fileSystemBean.sourceRoots}" nodes="#{item.directories}" >
​      <rich:treeNode>
​         #{item.shortPath}
​      </rich:treeNode>
​      <rich:treeModelAdaptor nodes="#{item.files}">
​         <rich:treeNode>#{item}</rich:treeNode>
​      </rich:treeModelAdaptor>
​   </rich:treeModelRecursiveAdaptor>
​</rich:tree>

​@ManagedBean
​@RequestScoped
​public class FileSystemBean {
​   private static final String SRC_PATH = "/WEB-INF";
​
​   private List<FileSystemNode> srcRoots;
​
​   public synchronized List<FileSystemNode> getSourceRoots() {
​      if (srcRoots == null) {
​         srcRoots = new FileSystemNode(SRC_PATH).getDirectories();
​      }
​      return srcRoots;
​   }
​}

​public class FileSystemNode {
​   ...
​   public synchronized List<FileSystemNode> getDirectories() {
​      if (directories == null) {
​         directories = Lists.newArrayList();
​         Iterables.addAll(directories, transform(filter(getResourcePaths(), containsPattern("/$")), FACTORY));
​      }
​      return directories;
​   }
​
​   public synchronized List<String> getFiles() {
​      if (files == null) {
​         files = new ArrayList<String>();
​         Iterables.addAll(files, transform(filter(getResourcePaths(), not(containsPattern("/$"))), TO_SHORT_PATH));
​      }
​      return files;
​   }
​
​   private Iterable<String> getResourcePaths() {
​        FacesContext facesContext = FacesContext.getCurrentInstance();
​        ExternalContext externalContext = facesContext.getExternalContext();
​        Set<String> resourcePaths = externalContext.getResourcePaths(this.path);
​        
​      if (resourcePaths == null) {
​         resourcePaths = Collections.emptySet();
​      }
​      return resourcePaths;
​   }   
​   ...
​}