Java Collection Framework

Collection Frame

A collection is also a container for storing data. An array that is primarily used to "override" an indeterminate number of objects.
Collections are used to store objects , and collections are distinguished from arrays because the set length is variable .
The collection container has many kinds, because the container itself has different characteristics, the internal data structure is different, and the container system is formed.

1, Set frame system:

2, the difference between an array and a collection

Arrays can store both the base data type and the reference data type, the base data type stores the value, and the reference data type stores the address value
A collection can store only reference data types (objects) in a collection or store basic data types, but it is automatically boxed into objects when stored
The array length is fixed and does not grow automatically.
The length of the collection is variable and can grow depending on the element's increase.

Java Collection Framework