import java.io.File;
     
    public class Main {
       public static long getFileSize(String filename) {
          File file = new File(filename);
          if (!file.exists() || !file.isFile()) {
             System.out.println("File doesn\'t exist");
             return -1;
          }
          return file.length();
       }
       public static void main(String[] args) {
          long size = getFileSize("c:/java.txt");
          System.out.println("Filesize in bytes: " + size);
       }
    }