In this data structure, a reference variable contains a reference to the first (or top) node; each node (except for the last or bottom node) links to the next one; and the last node’s link field ...

In contrast, a data structure is a concrete implementation of one or more ADTs, similar to how Java classes implement interfaces. Examples of ADTs include Employee, Vehicle, Array, and List.

This cheat sheet, from Princeton University's Introduction to Programming in Java course, makes a great reference for the basics you need to know, like structure, input/output, data types, and ...