Java Collections

Java inbuilt LinkedList Java inbuilt LinkedList class uses doubly linked list as internal data structure to store its elements. It is subclass of AbstractList and implements List and Deque interfaces. Insertion and deletion of elements is faster than ArrayList as it interally uses double LinkedList. Print LinkedList using a for loop The most common method […]

In this post, we will learn java set to array conversion. There are many ways to convert set to an array. 1. Using Java 8’s Stream If you are using Java 8, I would recommend using Java 8 Stream. [crayon-6729cdb49a898286149783/] Output [John, Martin, Mary] 2. Using toArray() We can directly call toArray() method on set […]

Learn about how to print ArrayList in java in different ways.

Learn about how to create deep copy of ArrayList in different ways.

In this article, we will learn to initialize ArrayList with values in Java. ArrayList is an implementation class of List interface in Java. It is used to store elements. It is based on a dynamic array concept that grows accordingly. We can Initialize ArrayList with values in several ways. Let’s see some of them with […]

In this post, we will see about Java 8 PriorityQueue. When the objects are supposed to be processed on the basis of their priority, in that scenario we use PriorityQueue. It’s a special type of queue (also, unbound queues) where the elements can be ordered either as per their natural ordering or based on a […]

In this post, we will see how to create 2d Arraylist in java. Best way to create 2d Arraylist is to create list of list in java. [crayon-6729cdb49c01a542295219/] Let’s create a program to implement 2d Arraylist java. [crayon-6729cdb49c020479762162/] Output: 2nd element in list3 : List3_Str2 3nd element in list1 : List1_Str3 1st element in list2 […]

Most common interview questions are <code>How HashMap works in java</code>, “How get and put method of HashMap work internally”. Here I am trying to explain internal functionality with an easy example. [crayon-6729cdb49c696137930475-i/]  is one of the most used Collections in java.Rather than going through theory, we will start with example first, so that you will […]

In this post, we will see how to sort HashSet in java. HashSet is a collection which does not store elements in any order. You might come across a situation where you need to sort HashSet. There can be many ways to sort HashSet, we will see two methods here. Using TreeSet You can use […]