测试Consumer类

public class testConsumer {
    public static void main(String[] args) {
        Consumer c = x -> {
            String y = "2";
            System.out.println(x + y);
        };
        c.accept(1);

    }
}

运行结果：

12

Process finished with exit code 0

解释：
c.accept(1);传入输入参数x=1，此时执行x+y即为1+“2”为12

Consumer类的源码如下：

@FunctionalInterface
public interface Consumer {

    
    void accept(T t);

    
    default Consumer andThen(Consumer after) {
        Objects.requireNonNull(after);
        return (T t) -> { accept(t); after.accept(t); };
    }
}