Roy Tutorials

Introduction Here I am going to tell you how to manually move WordPress site to local server. In this tutorial I am going to show you only the manual process and I won’t use any plugin to move live WordPress site to local server. I will show you here how to move your live WordPress site from shared hosting as…

In this tutorial I am going to show you how to configure PHP, MySQL, Apache HTTP Server for developing PHP based web applications. You may create PHP based standalone applications or web based applications and you want to run them in development environment before deploying into the production or live environment. I will also show you how to enable mod_rewrite…

Introduction Apache POI is the most popular library when comes to manipulate word, excel, ppt based documents. In this example I am going to show you how to read large excel file using Apache POI library. Your large excel file may contain various kind of information, such as, Human Resource data, Sales data, Credit Cards, Bank Transactions, etc. The large…

REST Services In this tutorial I am going to show you how to call Spring REST APIs concurrently using Java CompletableFuture. So basically REST service APIs will be invoked parallelly and in parallel execution the response time will be very less. I am going to show you how to call REST APIs concurrently using Java 8 or later’s new feature…

In this example you will see what are Predicate and Function functional interfaces in Java 8 or later version of Java. Functional interfaces provide target types for lambda expressions and method references. Each functional interface has a single abstract method, called functional method for that functional interface, to which the lambda expression’s parameter and return types are matched. The Predicate…

Introduction Here in this tutorial I am going to discuss about working principle of content security policy (CSP) in web applications. What if you want to minimize attacks on your website, what if you want to restrict the content to be displayed on your web site for some security reasons, what if you want to prevent Cross Site Scripting (XSS)…

Introduction Here in this tutorial I am going to show you how to work with Apache Kafka consumer and broker failover in multi-broker clusters. Kafka is a distributed event streaming platform that lets you read, write, store, and process events (also called records or messages in the documentation) across many machines. Example events are payment transactions, geolocation updates from mobile…

File Download Here in this tutorial I am going to show you how to download large file using Spring REST API. Generally when you download a file, your file is stored into file system or you load it into memory as a byte array. This is not a problem when you deal with a small file but when you download…

Introduction Here in this tutorial I am going to show you how to use AJAX technique using jQuery with Spring Boot application to check user availability instantly without refreshing the web page. I am going to use Thymeleaf template in Spring Boot application. I will use Spring REST to create REST API endpoint which will be called from jQuery code….

In this example I am going to show you how to upload and play video using flask framework. Flask is a light weight web framework used to rapidly develop web applications in Python programming language. I am not validating the file type here but it is always good idea to validate the file type before user can upload the file…