Quick way to encrypt your objects in Java

Hi, hope you have a good Christmas :) Mine was not bad, but here I am to write a little more.
Besides eating chocolates, these days I have continued some of my school works. One in specific is a game for android, that soon I will talk more in detail.

 
One important thing in games is the possibility of save the scores in a way that no one can forge, at least directly. So how do this in Java?

The simplest idea that I remembered was to put the scores in a particular class, make it serializable, apply a xor and write it to a file, to recover do the reverse process.

Downloading files in Java via HTTP

Today a friend of mine asked me a small piece of code for an Android application that allows downloading a file via HTTP from a remote server and save it to a local file. I looked in my documents and quickly found a small download manager that did precisely that.
But now I will share with you a class in Java (android or not) that takes as argument a URL and the destination file and download it. Remember that this code is very basic and is only to give ideas.

public class DownloaderClass {
    public void downloadFile(URL url, File outputFile) {
        int BUFFER_SIZE = 4096;
       
        InputStream in = null;
        FileOutputStream fos = null;
       
        try {
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.connect();

            if (conn.getResponseCode() / 100 != 2) {
                throw new RuntimeException("Response Code: " + conn.getResponseCode());
            }
           
            in = conn.getInputStream();
            fos = new FileOutputStream(outputFile);

            byte data[] = new byte[BUFFER_SIZE];
            int numRead;
            while (((numRead = in.read(data)) != -1)) {
                fos.write(data, 0, numRead);
            }
        } catch (IOException e) {
            System.out.println(e);
        } finally {
            if (fos != null) {
                try {
                    fos.close();
                } catch (IOException e) {
                }
            }

            if (in != null) {
                try {
                    in.close();
                } catch (IOException e) {
                }
            }
        }
    }
}

To use it, you just need 2 lines of code in your main.

DownloaderClass dc = new DownloaderClass();
dc.downloadFile(new URL("http://hackedprojects.blogspot.com/favicon.ico"),new File("c:\\favicon.ico"));

As you can see, it's simples :P

Read text file line-by-line in Java

I know that it's simple, but I'll leave it here.

DataInputStream dis = null;
try {
   dis = new DataInputStream(new FileInputStream("file.txt"));
   BufferedReader br = new BufferedReader(new InputStreamReader(dis));
   String line;
   while ((line = br.readLine()) != null) {
      System.out.println(line);
   }
} catch (Exception e) {
   System.err.println(e.getMessage());
}finally{
   try {
      dis.close();
   } catch (IOException ex) {}
}

Data types conversions in java

In the last weeks I've been programming in Java for 2 school works and others 3 more projects, I'm the type of person how prefer thing more low-level, so I can say that I never used it so much in so little time. The good thing about that is that I'm finally learning many things about objects and events, it's just like a new world.

So I have been taking notes and I'll share a little about a thing that I always forget, how to convert between data types commonly used.