String element="AppSample"

File file = new File("a.txt");
FileInputStream fis = new FileInputStream(file);
byte[] data = new byte[(int)file.length()];
fis.read(data);
fis.close();
//
String s = new String(data, "UTF-8");

if(s.contians(element){ ???Then.....

BufferedReader br = null;

        try {

            String currentLine;
                        int count;

            br = new BufferedReader(new FileReader("a.txt"));

            while ((currentLine = br.readLine()) != null && currentLine.contains("AppSample")) {
                count++;
            }

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (br != null)br.close();
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }

System.out.println("Count: "+count);