Read content from file.

ReadContentFromFile.java

    private static String readFile() throws IOException {
        FileInputStream stream = new FileInputStream(new File("String.txt"));
        try {
          FileChannel fc = stream.getChannel();
          MappedByteBuffer bb = fc.map(FileChannel.MapMode.READ_ONLY, 0, fc.size());
          /* Instead of using default, pass in a decoder. */
          return Charset.defaultCharset().decode(bb).toString();
        }
        finally {
          stream.close();
        }
    }