import java.util.ArrayList;
import java.util.Collections;

public class essai {
    public static void main(String[] args) {
        ArrayList<String> a = null;
        a = new ArrayList<String>(4); // <- pas la taille, mais la capacité
        a = new ArrayList<String>(Collections.nCopies(10, "toto"));
        // for (int i = 0; i < 5; i++)
        //     a.add("x" + i);
        a.set(5, "la");
        System.out.println(a);
        for (String s : a)
            System.out.println(s);
    }
}