Hello there everyone! Welcome back to our blog once again. Like always, we are going to learn something very exciting today. Today, we shall look into what is Lambda Expression in Java or in other words, how Lambda Expression works in Java. But, before we get into this topic, let me share with you that Lambda Expression is such a hot topic in the industry right now such that in almost every interview you shall encounter lots of questions on this Lambda Expression. It is extremely important to understand it working so that you are able to visualize how it works and also it would enable you to u ..read more

Hello everyone! Welcome back to the blog once again. In this post, we shall discuss about the Functional Interfaces in java. Let’s go through this concept step by step. First of all, let’s have a look at the technical definition. Definition A functional interface is an interface which can contain only single abstract method. It is just like any other interface in Java (whether Java has provided or you’ve created one) but with a condition that it should only contain one abstract method only. Point to remember As I just mentioned that it should only contain single abstract method that means the ..read more

Hello everyone! welcome once again to my blog. In this post we would try to understand the concept of DAO. It is closely related with DTO. I’d suggest you to checkout my post on DTO as it covers everything you need to know. What is DAO? DAO stands for Data Access Object which is an object representation of computed data to be returned from a procedure (or method or function or API). Where it is used and how? Let’s have a look at the use case in JavaScript to understand why we need to use it and then we would map this concept in Java as well. Here is some JavaScript code where we have exposed a ..read more

Hello everyone! Thank you for visiting my blog once again. I am pretty much sure that if you’ve more than an year of experience in Software Development and Engineering then you might have encountered the term DTO plenty of times in conjunction with DAO (Data Access Object). In this post we are going to cover only DTO and in subsequent posts I would like to cover up DAO as well. What is DTO? DTO is data transfer object and is widely used in enterprise level software solutions. It is also known as a DTO Design Pattern because of the skill it provides to write up the clean and understandable code ..read more

Hello everyone! I am back with one more important topic extends vs implements keywords in java. Assuming that you have some idea about Inheritance in java. Let’s discuss one by one with a real life example. Starting with extends, suppose there is an industry that produce Human Beings. Just assume! as we can’t do that. Every time when industry produces a Human Being (male/female) it has to manufacture eyes, nose, ears, legs and other organs for each of them. These are some of the organs that everyone should have. It would be nice to have a separate department who is responsible for creating suc ..read more

Today we are going to discuss about why variables/objects have to be final (or effectively final) when using inside an lambda expression (or anonymous inner class). I can feel your frustration as you might be wandering from blog to blog to get your doubts clear. Well, you’ve come to the right place. Fasten your seat belts as you are going to lose control when you’d be able to understand this logic. Let’s have a look at the following small program. We would refer to this program to understand this enforcement by the JVM. EffectivelyFinalDemo.java package com.blogging.lambda; import java.ut ..read more

If you’ve just moved into Java 8 and started dealing with Lambda expression then you might be wondering about lots of things. How, when, where etc. etc. We’ll discuss about Lambda expression in Java in a separate post and for now would concise ourselves up-to Method Referencing only. The whole concept is related to functional programming which was introduced in Java 8. In short, functional programming is nothing but dealing with functions only. JavaScript follows it very beautifully. Functional programming says that: To solve a problem, we would use a pure function which would accept function ..read more

Hello everyone! In the series of Design Patterns today we are going to discuss Observer design pattern. It is one of the Behavioral Design Patterns. As name itself suggests that it is used to observe change in object’s behavior or state. It can be think of an event generation and triggering some tasks. In this case, listener object never polls the interested object if it has changed it’s state or not. Listener object register itself to the interested object and says, “Hey! when you’ll change your state just let me know. I have to do something as per your changed state.”. One-to-many relationsh ..read more

Building Design Pattern is one of the Creational Design Patterns. In this design pattern we create small parts of an object and then we arrange them as per requirement to create the final object. For example, you are a car builder. You can manufacture car’s Tyre, then it’s engine, then body, then interior and finally you can arrange all of these parts of a car to build a complete car. Also you can make sure that while arranging parts of a car, it must have wheels else you will not build it. That means, there is a pretty much good scope for validations as well. So in short, builder design patte ..read more

Facade Design Pattern is one of the Structural Design Patterns. Facade Design Pattern says that the concept of Facade is similar to a building’s face. When you look at a building you find it beautiful and easy to use (whether it is for living or any other commercial stuffs you want to do with it). But you aren’t aware of it’s wiring, plumbing and other internal complexities. And even I think that one should not care about those stuffs as your focus is either staying there or doing some other tasks within the building. That is what Facade Design Pattern says. It says that client should not be a ..read more