Duvida no uso Manager pra encontrar arquivo com erro java.lang.NullPointerException

AplicacaoWeb
  - WebContent
    - html
       - pag01.html

package br.com.action.resposta

private String  readFileHTML(int statusHTML){
		String textoHTML = null;
		FileInputStream fis = null;
		BufferedInputStream bis = null;
		DataInputStream dis = null;
		URL url = null;
		try{
			if (statusHTML==1){
			    url = Manager.class.getResource("/html/pag01.html");
				File file = new File(url.getFile());
				fis = new FileInputStream(file);
				// Here BufferedInputStream is added for fast reading.
			    bis = new BufferedInputStream(fis);
			    dis = new DataInputStream(bis);
			    while (dis.available() != 0) {
			          System.out.println(dis.readLine());
			          textoHTML = textoHTML +dis.readLine();
			    }
			}

java.lang.NullPointerException