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.

See below some Java 8 (no Eclipse Collections) examples. ... You can see we have type support for both JDK as well as Eclipse Collections data structures, and also primitive collections.

Even the most complicated classes in Java can be flattened down to nothing more than the set of primitive data types they represent. But primitive types aren’t objects, and that presents a problem.