关于for循环为空不需要判断的问题

关于网上说的增强式for和普通for循环为空不需要判断的问题:

public class testData {
    public static void main(String[] args) {
        List<String> list = new ArrayList<>();
        for ( String str:list){
            System.out.println("11");
        }
        for (int i = 0; i < list.size(); i++) {
            System.out.println("22");
        }
        list=null;
        for ( String str:list){
            System.out.println("11");
        }
        for (int i = 0; i < list.size(); i++) {
            System.out.println("22");
        }
    }
}public cla