java 13 interview questions and answers

Map is Interface which is part of Java collections framework. This is to store Key Value pair, and Hashmap is class that implements that using hashing technique. In Core Java: Map: A Map is an interface in Java that represents a collection of key-value pairs, where each key is associated with exactly one value. It … Read more

Iterator : Enables you to traverse through a collection in the forward direction only, for obtaining or removing elements ListIterator : extends Iterator, and allows bidirectional traversal of list and also allows the modification of elements. In Java, java.util.Iterator and java.util.ListIterator are both interfaces that belong to the java.util package and are used for iterating … Read more

Some of the collection classes provide traversal of their contents via a java.util.Iterator interface. This interface allows you to walk through a collection of objects, operating on each object in turn. Remember when using Iterators that they contain a snapshot of the collection at the time the Iterator was obtained; generally it is not advisable … Read more

Java Collections framework API is a unified architecture for representing and manipulating collections. The API contains Interfaces, Implementations & Algorithm to help java programmer in everyday programming. In nutshell, this API does 6 things at high level Reduces programming efforts. – Increases program speed and quality. Allows interoperability among unrelated APIs. Reduces effort to learn … Read more

TreeSet – It is the implementation of SortedSet interface.This implementation provides guaranteed log(n) time cost for the basic operations (add, remove and contains). The class is not synchronized. In Core Java, a TreeSet is a class that implements the Set interface and extends the AbstractSet class. It is part of the Java Collections Framework and is … Read more