// Write a Java program that reads a file and throws an exception if the file is empty.
              import java.io.File;
              import java.io.FileReader;
              import java.io.IOException;
              
              class EmptyFileException extends Exception {
                  public EmptyFileException(String message) {
                      super(message);
                  }
              }
              
              class CheckEmptyFile {
                  public static void main(String[] args) {
                      try {
                          checkFileNotEmpty("data.txt");
                      } catch (EmptyFileException e) {
                          System.out.println("Empty file detected: " + e.getMessage());
                      } catch (IOException e) {
                          System.out.println("File not found or cannot be read: " + e.getMessage());
                      }
                  }
              
                  public static void checkFileNotEmpty(String fileName) throws IOException, EmptyFileException {
                      File file = new File(fileName);
              
                      if (!file.exists() || file.length() == 0) {
                          throw new EmptyFileException("File is empty or does not exist.");
                      }
              
                      FileReader reader = new FileReader(file);
                      reader.close();
                  }
              }