java arraylist ensureCapacity无法正常工作

import java.util.ArrayList;

public class Main {
    public static void main(String[] args) {
        ArrayList<String> list = new ArrayList<>();
        list.add("Hello");
        list.add("World");

        System.out.println("List size: " + list.size()); // 输出：List size: 2

        list.ensureCapacity(10);
        System.out.println("New list size: " + list.size()); // 输出：New list size: 10
    }
}

import java.util.ArrayList;

public class Main {
    public static void main(String[] args) {
        ArrayList<String> list = new ArrayList<>();
        list.add("Hello");
        list.add("World");

        System.out.println("List size: " + list.size()); // 输出：List size: 2

        // 在添加元素之前调用 ensureCapacity
        list.ensureCapacity(10);
        System.out.println("New list size: " + list.size()); // 输出：New list size: 10
        
        // 添加元素
        list.add("Another element");
        System.out.println("New list size: " + list.size()); // 输出：New list size: 11
    }
}