Getting size and comparing attribute value from ArrayList in other class

I am trying to create a method which creates a result for a athlete in a competition. I have an ArrayList with the athletes in another class and now I want this method to be able to find the size of the ArrayList and also compare one int attribute of every Athlete with the input number. This is what I have so far, Im really stuck. So my quetions to you are: How do I get my for loop to see the size of the ArrayList athletes? and what is a proper way to check whether or not the input has a matching athlete in the ArrayList(I want it to print out if there is no match)? Thank you

    public class ResultList {
Scanner scanner = new Scanner(System.in);
ArrayList<Result> resultList = new ArrayList<Result>();

public ResultList() {
     ArrayList<Athlete> temp = new AthleteList().getArrayList();
}

void addResult() {
    int competetionNumber;
    System.out.print("What is the athletes competetionnumber?");
    competetionNumber = scanner.nextInt();
    scanner.nextInt();
    for (int i = 0; i < athletes.size(); i++) {

    }
}
}

Other class with the Athlete ArrayList:

    public class AthleteList {
ArrayList<Athlete> athletes = new ArrayList<Athlete>();
public AthleteList () {

}
     public ArrayList<Athlete> getArrayList() {
     return athletes;
}