What is WeakHashMap WeakHashMap is based on Hash table implementation of the Map interface but with weak keys. An entry in a WeakHashMap will automatically be removed when its key is no longer in ordinary use. When a key has been discarded due to weakness characteristics of keys its entry is effectively removed from the map, so this class behaves…

What is LinkedHashMap A LinkedHashMap like HashMap is a simple yet powerful way to store and get data. Unlike HashMap, LinkedHashMap is based on HashTable and Linked list implementation of the Map interface and stores items as key/value pairs. Like HashMap, LinkedHashMap permits only unique keys. It also permits only one null key (whereas HashTable does not allow any null…

Iterator pattern falls under behavioral design pattern. Iterator pattern is very commonly used design pattern in Java. This pattern is used to iterate through a collection of objects without exposing its underlying representation. It is used to access the elements of an aggregate object sequentially. For example, Java’s collections like ArrayList and HashMap have implemented the iterator pattern.