This means that Java uses classes and objects to create ... whether or not we can see it on the screen. Thus it is a data object. The class is the piece of code that creates the data object.

Listing 1. A simple data class in Java public class Musician { private Long id; private String name; private Instrument mainInstrument; private ArrayList performances = new ArrayList(); public ...

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.