Core Interfaces. Collection: It is the collection hierarchy’s root interface. It stands for a collection of items referred to as elements. More specialised sub interfaces like List, Set, and Queue ...

java.lang: A collection of language-related classes, such as Object and String, organized in the java package’s lang subpackage; java.lang.ref: A collection of reference-related language classes ...

Guava is a set of core Java libraries from Google that includes new collection types (such as multimap and multiset), immutable collections, a graph library, and utilities for concurrency, I/O, ...

HashMap in Java. In a nutshell, Collection framework provides utility classes and interfaces that are readymade implementation of various data structures and algorithms. Whereas, Map interface ...