Java - How Can I Write My ArrayList to a file, and Read (load) that file to the original ArrayList?

You should use Java's built in serialization mechanism. To use it, you need to do the following:

1. Declare the Club class as implementing Serializable:

   public class Club implements Serializable {
       ...
   }
   

   This tells the JVM that the class can be serialized to a stream. You don't have to implement any method, since this is a marker interface.

2. To write your list to a file do the following:

   FileOutputStream fos = new FileOutputStream("t.tmp");
   ObjectOutputStream oos = new ObjectOutputStream(fos);
   oos.writeObject(clubs);
   oos.close();
   

3. To read the list from a file, do the following:

   FileInputStream fis = new FileInputStream("t.tmp");
   ObjectInputStream ois = new ObjectInputStream(fis);
   List<Club> clubs = (List<Club>) ois.readObject();
   ois.close();
   

As an exercise, I would suggest doing the following:

public void save(String fileName) throws FileNotFoundException {
    PrintWriter pw = new PrintWriter(new FileOutputStream(fileName));
    for (Club club : clubs)
        pw.println(club.getName());
    pw.close();
}

This will write the name of each club on a new line in your file.

Soccer
Chess
Football
Volleyball
...

I'll leave the loading to you. Hint: You wrote one line at a time, you can then read one line at a time.

Every class in Java extends the Object class. As such you can override its methods. In this case, you should be interested by the toString() method. In your Club class, you can override it to print some message about the class in any format you'd like.

public String toString() {
    return "Club:" + name;
}

You could then change the above code to:

public void save(String fileName) throws FileNotFoundException {
    PrintWriter pw = new PrintWriter(new FileOutputStream(fileName));
    for (Club club : clubs)
         pw.println(club); // call toString() on club, like club.toString()
    pw.close();
}

In Java 8 you can use Files.write() method with two arguments: Path and List<String>, something like this:

List<String> clubNames = clubs.stream()
    .map(Club::getName)
    .collect(Collectors.toList())

try {
    Files.write(Paths.get(fileName), clubNames);
} catch (IOException e) {
    log.error("Unable to write out names", e);
}