Signed Applet - Problem reading large local files

Question

Hello,
I am using a signed applet (self-signed) to read files from a clients machine (local file system). Following is the code for buffered reading (the meat):
String thisLine, ret = "";
try{
     BufferedReader myInput = new BufferedReader(new FileReader(fn));
     while ((thisLine = myInput.readLine()) != null) {
     ret += thisLine + "\n";
     myInput.close();
catch (Exception e) {
     ret = "Cannot load, exception!";
When I read a file <= 512KB, it runs fine/as expected. Now, when I read a file, say for example 1024KB in size, I expect the application to take twice as much time (than 512KB file) and read the file, but instead the applet/browser hangs. As a matter of fact I am not able to read files > 512KB.
So, is there a limit on file size (from local file system) when reading from an applet, or is it to do with the way I am reading it?
Any help, suggestions or comments would be highly appreciated.
Thanks in advance.

Answer 1

Here is how I read a file from my applet:
     private String getData(String u) {
          URL url = null;
          InputStream in = null;
          String ret = null;
          try {
               // the following line wil read a file @ the same location as your class file
               // this way your applet does not need any special privileges
               // you could change the url to a file if so needed
               url = new URL(this.getCodeBase(), u);
               URLConnection conn = url.openConnection();
               // next line is optional and just tells the http server
               // a utf-8 response is accepted
               // some servers will return a bad request
               conn.setRequestProperty("Accept-Charset","utf-8");
               // first try to find out if the server has
               // provided us with the charset of the response
               // since this doesn't work with the msjvp (version 1.1.2)
               // it's commented out
               // instead provide a charEncoding yourselve
               String charEncoding = "UTF8";
//               int i = conn.getHeaderFields().size()-1;
//               while(i>-1){
//                    System.out.print(conn.getHeaderFieldKey(i));
//                    System.out.print("=");
//                    System.out.println(conn.getHeaderField(i));
//                    if(conn.getHeaderField(i).toLowerCase().indexOf("charset")!=-1){
//                         String charsetLine = conn.getHeaderField(i).toUpperCase();
//                         if(charsetLine.indexOf("SHIFT_JIS")!=-1){
//                              charEncoding = "Shift_JIS";
//                         if(charsetLine.indexOf("EUC-JP")!=-1){
//                              charEncoding = "EUC-JP";
//                    i--;
               // here is the value for char encoding (as a parameter in the <object html tag)
               if(this.getParameter("dataCharset")!=null){
                    charEncoding=this.getParameter("dataCharset");
               // wither you have a file or an url you read from an inputstream
               // here is how it's done
               // read the whole file and than turn it into a string
               in = conn.getInputStream();
               ByteArrayOutputStream bos = new ByteArrayOutputStream();
               int len;
               byte[] buf = new byte[1024];
               while ((len = in.read(buf)) > 0) {
                    bos.write(buf, 0, len);
               in.close();
               // you have the file as a byte array (bos.toByteArray()
               // here is how you turn it into a string
               ret = new String(bos.toByteArray(),charEncoding);
          } catch (Exception e) {
               e.printStackTrace(System.out);
          return ret;
     }