Article From:https://www.cnblogs.com/lu51211314/p/9121536.html
Among them, item in red box refers to one of the collections. When a new collection is formed, exclude a certain item. It means that the new set contains only the conditions (item.equals).“2”)）One item.
The above is my own understanding. If there is a better description, please leave a message.
Link of this Article: The filter of the usage of stream in jdk8 (I)