First look at the frame diagram of a java collection:
Image source https://www.runoob.com/java/java-collections.html
The above picture is a complete Java collection framework diagram. As you can see from the above picture, the Java collection framework can be classified into two types as a whole. One is a collection that implements the Collection interface, and the other is a Map; next we will only be developing for us Commonly used content is organized:
Java collection framework-List
Java collection framework-Map
Java collection framework-Set