Category: Java Collections

Java Collection Interview Questions and Answers

Most Important HashMap Interview Questions and Answers

In this post I am sharing most important HashMap interview questions along with answers. Java collections package is java.util, this is the most important package and used frequently in most of the projects. What are the methods required for an object to be used as a key or value in HashMap equals() hashcode() The key […]

What is difference between Vector and ArrayList in Java?

Classes and Objects interview questions

Here is list of my favorite, frequently asked Questions from Java collection framework. Almost all of these questions have appeared in Java interview at various level ranging from Junior to Senior software engineer level. ArrayList and Vector are two of most used class on java collection package What is difference between Vector and ArrayList in Java? […]

What is difference between List, Set and Map

Classes and Objects interview questions

1. What is difference between List, Set and Map? List List is an ordered collection. List allows duplicate elements. List allows null elements and also store many null elements because it allows duplicate elements. The following most useful classes implementing List interface 1. ArrayList  2. LinkedList  3. Vector Set Set is unordered collection. Set does not […]