Java Collections Archive

TreeMap class A TreeMap contains values based on the key. It implements the NavigableMap interface and extends AbstractMap class. It contains only unique elements. It cannot have null key but can have multiple null values. …

This class extends HashMap and maintains a linked list of the entries in the map, in the order in which they were inserted. This allows insertion-order iteration over the map. That is, when iterating a …

HashMap class extends AbstractMap and implements Map interface. It uses a hashtable to store the map. This allows the execution time of get() and put() to remain same. HashMap has four constructor. HashMap() HashMap(Map< ? …

The Map interface is not an extension of Collection interface. Instead the interface starts of it’s own interface hierarchy, for maintaining key-value associations. The interface describes a mapping from keys to values, without duplicate keys, …

public class TreeSet<E> extends AbstractSet<E> implements NavigableSet<E>, Cloneable, Serializable A NavigableSet implementation based on a TreeMap. The elements are ordered using their natural ordering, or by a Comparator provided at set creation time, depending on …