You can do this to check all files inside WEB-INF folder
 String [] f=new File(getServletContext().getRealPath("WEB-INF")).list(); 
If you have below scenario and want to read properties file
SampleApp.war
   |
   |-------- myApp.properties
   |
   |-------- WEB-INF
                |
                |---- classes
                         |
                         |----- org
                                 |------ myApp
                                           |------- MyPropertiesReader.class
You have to do this 
    InputStream inputStream = this.getClass().getClassLoader()  
                .getResourceAsStream("myApp.properties");
    Properties properties = new Properties();  
    System.out.println("InputStream is: " + inputStream);  
    // load the inputStream using the Properties  
    properties.load(inputStream);    
You can do it also from ServletContext
 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
        ServletContext servletContext = getServletContext();
        String contextPath = servletContext.getRealPath(File.separator);
        PrintWriter out = response.getWriter();
        out.println("<br/>File system context path (in TestServlet): " + contextPath);
    }
Another way
    ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
    InputStream stream = classLoader.getResourceAsStream("FileName");
    if (stream == null) {
      // File not nound
    } else {
     // User stream object 
    }