A Guide to ConcurrentMap
1. Overview Maps are naturally one of the most widely style of Java collection. And, importantly, HashMap is not a thread-safe implementation, while Hashtable does provide thread-safety by synchronizing operations. […]
Month: July 2021
Guide to WeakHashMap in Java
1. Overview In this article, we will be looking at a WeakHashMap from the java.util package. In order to understand the data structure, we’ll use it here to roll […]
Java TreeMap vs HashMap
1. Introduction In this article, we’re going to compare two Map implementations: TreeMap and HashMap. Both implementations form an integral part of the Java Collections Framework and store data as key-value pairs. 2. Differences […]
A Guide to TreeMap in Java
1. Overview In this article, we are going to explore TreeMap implementation of Map interface from Java Collections Framework(JCF). TreeMap is a map implementation that keeps its entries sorted according […]
A Guide to Java HashMap
1. Overview In this article, we’ll see how to use HashMap in Java, and we’ll look at how it works internally. A class very similar to HashMap is Hashtable. Please […]
A Guide to HashSet in Java
1. Overview In this article, we’ll dive into HashSet. It’s one of the most popular Set implementations as well as an integral part of the Java Collections Framework. 2. […]
A Guide to TreeSet in Java
1. Overview In this article, we’ll have a look at an integral part of the Java Collections Framework and one of the most popular Set implementations – the TreeSet. […]
Reversing a Linked List in Java
1. Introduction In this tutorial, we’ll implement two linked list reversal algorithms in Java. 2. Linked List Data Structure A linked list is a linear data structure in […]
Finding the Differences Between Two Lists in Java
1. Overview Finding differences between collections of objects of the same data type is a common programming task. As an example, imagine we have a […]
How to Count Duplicate Elements in Arraylist
1. Overview In this short tutorial, we’ll look at some different ways to count the duplicated elements in an ArrayList. 2. Loop with Map.put() Our expected result […]
Intersection of Two Lists in Java
1. Overview In this tutorial, we’ll learn how to retrieve the intersection of two Lists. Like many other things, this has become much easier thanks to the introduction […]
Ways to Iterate Over a List in Java
1. Introduction Iterating over the elements of a list is one of the most common tasks in a program. In this tutorial, we’re going to […]
Remove the First Element from a List
1. Overview In this super-quick tutorial, we’ll show how to remove the first element from a List. We’ll perform this operation for two common implementations of […]
Add Multiple Items to an Java ArrayList
1. Overview of ArrayList In this quick tutorial, we’ll show to how to add multiple items to an already initialized ArrayList. For an introduction to the use […]
Remove All Occurrences of a Specific Value from a List
1. Introduction In Java, it’s straightforward to remove a specific value from a List using List.remove(). However, efficiently removing all occurrences of a value is much harder. In this tutorial, […]
Copy a List to Another List in Java
1. Overview In this quick tutorial, we’ll show different ways to copy a List to another List and a common error produced in the process. For an introduction to […]
Java List UnsupportedOperationException
1. Overview In this quick tutorial, we’ll discuss a common Exception that can occur when working with some the API of most List implementations – the UnsupportedOperationException. A java.util.List has more functionality than […]
How to Find an Element in a List with Java
1. Overview Finding an element in a list is a very common task we come across as developers. In this quick tutorial, we’ll cover different […]
Check If Two Lists are Equal in Java
1. Introduction In this short article we’ll focus on the common problem of testing if two List instances contain the same elements in exactly the same order. […]
Removing all Nulls from a List in Java
This quick tutorial is going to show how to remove all null elements from a List, using plain Java, Guava, the Apache Commons Collections and the newer Java 8 lambda […]
