public class ForEachTest {
    public static void main(String[] args) {
        /** list */
//ArrayList in Arrays.forEach(Consumer<? super E> action)
Arrays.asList("a", "b", "d").forEach(e -> System.out.println(e));
//ArrayList.forEach(Consumer<? super E> action)
List<Integer> list = new 
 
ArrayList<>();
list.add(1);
list.add(2);
list.forEach(e -> System.out.println(e));
/** HashSet */
//HashSet.forEach(Consumer<? super T> action)
Set set = new HashSet<>(list);
set.forEach(e -> System.out.println(e));
/**  Stack / Vector */
Stack<String> stack = new Stack<>();
 
stack.push("A");
stack.push("B");
stack.push("C");
//Vector.forEach(Consumer<? super E> action)
stack.forEach(e -> System.out.println(e));
/**  map */
Map<String,String> map = new HashMap<>();
map.put("a", "a");
map.put("b", "b");
//KeySet in HashMap.forEach(Consumer<? super K> action)
 
map.keySet().forEach(e -> System.out.println(e));
//EntrySet in HashMap.forEach(Consumer<? super Map.Entry<K,V>> action)
map.entrySet().forEach(e -> {
            System.out.println(e.getKey());
System.out.println(e.getValue());
});
//Values in HashMap.forEach(Consumer<? super V> action)
map.values().forEach(e -> System.out.println(e));
//HashMap.forEach(BiConsumer<? super K, ? super V> action)
map.forEach((k, y) -> {
            System.out.println(k);
System.out.println(y);
});
}
}

執行forEach的時候不允許修改元素長度，否則會丟擲ConcurrentModificationException異常