reading a file, concatenating 10 lines into 1 string, but displaying whole file

how can i read from a file in java, then concatenate first 10 lines to a string based on lets say (end), then start reading from next lines and then concatenate next 10 lines to 1 string?

public class ReadingTextFile {
    public static void main (String [] args) throws IOException
    {
        String filename = "/home/ezkauha/Desktop/ipex.txt";
        String line = null;
       try
       {
           FileReader fileReader = new FileReader (filename);

            BufferedReader   bufferedReader = new BufferedReader (fileReader);
            while ((line = bufferedReader.readLine()) != null) 
            {
                System.out.println(line);
            }
            bufferedReader.close();
       } 

        catch(FileNotFoundException ex)
       {
           System.out.println ("unable to open file"); 
       }
    }
}