Hello guys, we are again with new article that is on Creating Class with methods and attributes in Java. The main aim of this article is to give you idea about how to declare a class or method in Java and about different ways of declaring. In the world of Java programming, classes serve as the fundamental building blocks for creating objects and defining the structure of your applications. These classes encapsulate data and behavior, allowing you to model real-world entities and implement the logic that governs their interactions.
How to convert a List to Array in Java? Example Tutorial
There is no easy way to convert an array to a list in Java, but you can easily convert a list into an array by calling the toArray() method, which List inherits from the Collection interface. If you solely rely on core JDK, then the only way to convert an array to a list is by looping over the array and populating the list one element at a time. But if you can use open source libraries like Google Guava or Apache Commons lang then there are many utility classes to convert list to array and vice-versa, as shown in this tutorial. If you are working on a Java application, you will often need to convert between list and array.
How to search a LinkedList in Java? Example
You can search an element inside LinkedList in Java by using indexOf() and lastIndexOf() methods. Though LinkedList doesn't support random search like ArrayList, you can still go through the list, check each element and find out whether it's an interesting element or not. Since java.util.LinkedList is an implementation of a doubly-linked list, these two methods are quite handy to search from either end e.g. indexOf() method starts the search from the head and returns an element's position while lastIndexOf() starts the search from the tail. Though the position is not relative to the ends, they are always calculated from the head.
How to get first and last elements form ArrayList in Java
There are times when you need to get the first or last element of an ArrayList. One of the common scenarios where you need the first and last element of a list is supposed you have a sorted list and want to get the highest and lowest element? How do you get that? The first element is your lowest and the last element is your highest, provided ArrayList is sorted in ascending order. If it's opposite then the first element would be the maximum and the last element would be the minimum. This is quite easy to do in ArrayList because the first element is stored at index 0 and the last element is on index, size - 1.
Difference between synchronized ArrayList and CopyOnWriteArrayList in Java?
What is the difference between a CopyOnWriteArrayList and a Synchronized ArrayList is one of the popular Java interview questions, particularly for beginners with 1 or 2 years of experienced programmers. Though both synchronized ArrayList and CopyOnWriteArrayList provide you thread-safety and you can use both of them when your list is shared between multiple threads, there is a subtle difference between them, Synchronized ArrayList is a synchronized collection while CopyOnWriteArrayList is a concurrent collection. What does this mean? It means is that CopyOnWriteArrayList is designed keeping concurrency in mind and it is more scalable than synchronized ArrayList if the list is primarily used for reading.
PriorityQueue in Java? Example Tutorial
PriorityQueue is another data structure from the Java Collection framework, added in Java SE 5. This class implements the Queue interface and provides a sorted element from the head of the queue. Though it provides sorting, it's a little different from other Sorted collections e.g. TreeSet or TreeMap, which also allows you to iterate over all elements, in the priority queue, there is no guarantee on iteration. The only guaranteed PriorityQueue gives is that the lowest or highest priority element will be at the head of the queue. So when you call remove() or poll() method, you will get this element, and next on priority will acquire the head spot. Like other collection classes which provide sorting, PriorityQueue also uses Comparable and Comparator interface for priority.
10 Common Coding Mistakes Every Java Developers Should be aware of
Hello guys, Java is a versatile and powerful programming language, but it's not immune to common coding mistakes that developers may inadvertently make. These errors can lead to unexpected behavior, performance issues, and even security vulnerabilities. In this article, I am going to share 10 such common coding mistakes Java developers often encounter, provide examples of each mistake, explain why they are problematic, and offer solutions to correct them. I strongly recommend every Java developer whether he is beginner, intermediate or senior developer to go through the list once so that you are aware of these mistakes. If you have been coding in Java then most likely you would have also made the same mistake, if you do, let us know in comments so that we all can learn from each other.
10 Examples of HashMap in Java - Programming Tutorial
The HashMap in Java is one of the most popular Collection classes among Java programmers. After my article on How HashMap works in Java, which describes the theory part of Java HashMap and becomes hugely popular among Java programmers, I thought to share how to use HashMap in Java with essential and fundamental HashMap examples, but couldn't do that earlier and it was slipped but today we are here with all the HashMap examples about getting values to checking if a key exists in Map, I am going to share everything a Java developer should know about HashMap. The HashMap is a data structure, based on hashing, which allows you to store an object as a key-value pair, an advantage of using HashMap is that you can retrieve objects on constant time i.e. O(1) if you know the key.
How to convert a Map to List in Java? HashMap to ArrayList Example
Before converting a Map to a List in Java, we should be very clear about these data structures which are widely used in Java. So let's begin with Map. What is Map? Map is an Interface in Java which store key and value object. It's a Java representation of a popular hash table data structure that allows you to search an existing element in O(1) time, at the same time also makes insertion and removal easier. We use a key object to retrieve the value object by using hashing functionality provided by Map. As we have seen in how the get method of HashMap works, In Java, the equals() and hashcode() methods are an integral part of storing and retrieving objects from it. The map allows duplicate values but no duplicate keys.
Subscribe to:
Posts (Atom)