InputStream in=CrunchifyCreateXMLDOM1.xmlmain(); // CrunchifyCreateXMLDOM1.xmlmain() --тип //Outputstream
    Reader reader = new InputStreamReader (in);
    JTextArea textArea = new JTextArea();

    textArea.read(reader,null); // Непонятно что в даном случае как другой аргумент назначать,
   //Я назначил Null
    textArea.setSize(500,500);  

JTextArea textArea = new JTextArea();
    textArea.setSize(400,500);    
    textArea.setLineWrap(true);
    textArea.setEditable(true);
    textArea.setVisible(true);
    try {
    FileReader f = new FileReader("D:\\file.xml");
    BufferedReader b = new BufferedReader(f);
  
    boolean eof = false;
  
   while(! eof)
  {
  String lineIn = b.readLine();
  if(lineIn == null)
    {
    eof = true;
    }
  else
    {
    textArea.append(lineIn + System.getProperty("line.separator"));
    }
  }
  
   } catch (Exception e) {
            e.printStackTrace();
        }

public static void main(String[] args)
    {
        JFrame frame = new JFrame ("tt");
        frame.setSize(500,500);
        frame.setResizable(false);
    
    gui.xmlmain();
    
     PipedOutputStream po;
     PipedInputStream pi;
     try {
    po = new PipedOutputStream();
    pi=new PipedInputStream(po); 
     } catch (Exception e) {
            e.printStackTrace();
        }
    
    
    JTextArea textArea = new JTextArea();
    Reader reader = new InputStreamReader (System.in);
    try {
    textArea.read(reader,System.in);
     } catch (Exception e) {
            e.printStackTrace();
        }

        
    textArea.setSize(500,500);    
    textArea.setLineWrap(true);
    textArea.setEditable(true);
    textArea.setVisible(true);

    JScrollPane scroll = new JScrollPane (textArea);
    scroll.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
    scroll.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
    //frame.add(textArea);
    frame.add(scroll);
    frame.setVisible(true);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
    }

 try {
    textArea.read(reader,System.in); //textArea.read(reader,null) - то же самое
     } catch (Exception e) { 
            e.printStackTrace();
        }

public static ByteArrayInputStream xmlmain1 () throws Exception {
            DocumentBuilderFactory icFactory = DocumentBuilderFactory.newInstance();
            DocumentBuilder icBuilder;
            icBuilder = icFactory.newDocumentBuilder();
            Document doc = icBuilder.newDocument();
            Element mainRootElement = doc.createElementNS("http://crunchify.com/CrunchifyCreateXMLDOM", "File"+""+"System");
            doc.appendChild(mainRootElement);     
            Filewalker.walk("c:\\" );   
            for ( Filewalker fp : Filewalker.listed ) {    
            // append child elements to root element
            mainRootElement.appendChild(getCompany(doc, fp.name, fp.length, fp.path));}           
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            ElementToStream(doc.getDocumentElement(), baos);
            return new ByteArrayInputStream((baos.toByteArray()));
            }
                         
            public static void ElementToStream(Element element, OutputStream out) {
      try {
      DOMSource source = new DOMSource(element);
      StreamResult result = new StreamResult(out);
      //PrintStream p= PrintStream(out);
      //p.setOut(out);
      TransformerFactory transFactory = TransformerFactory.newInstance();
      Transformer transformer = transFactory.newTransformer();
      transformer.setOutputProperty(OutputKeys.INDENT, "yes");
      transformer.setOutputProperty(OutputKeys.METHOD, "xml");  
      transformer.transform(source, result);
      } catch (Exception ex) {
      }       
      }

Error at line 2
Document is invalid: no grammar found.
Error at line 2
Document root element "FileSystem", must match DOCTYPE root "null".