Java Learning---6. Common containers, streams

The API for the 1.java provided container is located within the Java.util package.

Set: cannot be repeated, unordered. List: Can be repeated, in order. Map: The mapping method for key-value pairs.

Collection c=new ArrayList ();

2. Generics: Use generics when using a collection, define the type of the collection when defining the collection. The readability and stability of the program can be enhanced.

3. Stream: Java streaming input/output principle:

Java Learning---6. Common containers, streams