Examining List and ArrayList
List is an interface implemented by the ArrayList class. Therefore, any API method in List is automatically in ArrayList. As we know, it is good coding practice to use an interface reference (List) to refer to an object (ArrayList). As the compiler looks at the reference type, this frees you up in the future to use different implementations of List, such as LinkedList.
Both List and ArrayList are in the java.util package. In the API, both are typed generically with E (for Element), which means we are free to specify the type we want to store in our list. Failure to follow the declared type results in a compiler error. We will cover generics in detail in Chapter 13.
List properties
A list is an ordered collection (sometimes called a sequence). We have precise control over where in the list an element is inserted. Indices (as with arrays) start at 0 and duplicate elements are allowed. The order that lists maintain is insertion order. In other words...
