Writing data array to the file is simple as shown in the code snippet below.

Java Code:
    try {
      // Create an output stream to the file.
      FileOutputStream file_output = new FileOutputStream (file);
      // Wrap the FileOutputStream with a DataOutputStream
      DataOutputStream data_out = new DataOutputStream (file_output);

      // Write the data to the file in an integer/double pair
      for (int i=0; i < i_data.length; i++) {
          data_out.writeInt (i_data[i]);
          data_out.writeDouble (d_data[i]);
      }
      // Close file when finished with it..
      file_output.close ();
    }
    catch (IOException e) {
       System.out.println ("IO exception = " + e );
    }