java util

you can import any package by this way; here I show you how to import java.util.list package

The Treemap is a component of the Java Collections Framework that implements the SortedMap interface. It keeps its elements ordered according to the natural ordering of keys or a defined comparator.

HashMap is a component of the Java Collections Framework that implements the Map interface. It offers a key-value pair data structure in which elements are stored as a combination of keys and their corresponding values. HashMap does not support duplicate keys, but it does support mapping multiple values to the same key. It provides constant-time performance for simple operations like as element addition, removal, and retrieval.

In Java, the LinkedList class implements the List interface and provides a doubly-linked list data structure. It provides a versatile means of storing and manipulating a collection of items. A LinkedList, unlike an ArrayList, uses references to connect components rather than contiguous memory allocation.