What is the difference between ArrayList and the List interface in Java, and how are they related?

List is an interface in Java that defines the behavior of an ordered collection of elements with access by index, addition, removal, and other operations. ArrayList is a concrete implementation of the List interface based on a dynamic array.

The relationship is that ArrayList implements the List interface, meaning it provides a specific mechanism for storing and managing elements that adheres to the interface's contract.

Example:

List<String> list = new ArrayList<>();
list.add("Example");
System.out.println(list.get(0));

Here, the variable is declared as List, which allows changing the implementation without modifying the code, and specifically, ArrayList is used.