public void createWebInf() throws CoreException {
   if (webInfDir == null) {
     IPath webInfPath = new Path(WEB_INF_PATH);
     webInfDir = rootFolder.getFolder(webInfPath);
     if (!webInfDir.exists()) {
       webInfDir.create(true, false, null);
       refreshWebInf();
     }
   }
 }