public class Test1 {
  public static void main(String[] args) {
    List<Integer> list = Arrays.asList(1,2,3,4,5,6,7,8,9,10);
    list.forEach(new Consumer<Integer>() {
      @Override
      public void accept(Integer integer) {
        System.out.println(integer);
      }
    });
  }
}

public interface Iterable<T> {
  .
  .省略
  .
  default void forEach(Consumer<? super T> action) {
    Objects.requireNonNull(action);
    for (T t : this) {
      action.accept(t);
    }
  }
}

@FunctionalInterface
public interface Consumer<T> {

  /**
   * Performs this operation on the given argument.
   *
   * @param t the input argument
   */
  void accept(T t);
  .
  .省略
  .
}

public class Test1 {
  public static void main(String[] args) {
    List<Integer> list = Arrays.asList(1,2,3,4,5,6,7,8,9,10);
    //Lambda表达式 接收一个参数 不返回值
    list.forEach(item -> System.out.println(item));
  }
}

public class Test1 {
  public static void main(String[] args) {
    List<Integer> list = Arrays.asList(1,2,3,4,5,6,7,8,9,10);
    //方法引用
    list.forEach(System.out::println);
  }
}

public void println(Object x) {
  String s = String.valueOf(x);
  synchronized (this) {
    print(s);
    newLine();
  }
}

public class Test1 {
  public static void main(String[] args) {
    List<Integer> list = Arrays.asList(1,2,3,4,5,6,7,8,9,10);
    //构造方法引用
    list.forEach(Test1::new);
  }
  
  Test1(Integer i){
    System.out.println(i);
  }
}