Roy Tutorials

Table of Contents Introduction Prerequisites Project Setup Merge Cells in Excel Testing Merged Cells Source Code Introduction Here I am going to show you how to merge cells in excel sheet using Apache POI in Java programming language. In other words I will merge two or more columns from single row or multiple rows in excel file using Java with…

Table of Contents Introduction Why do you need to pretty print JSON data? Prerequisites Pretty Print JSON Source Code Introduction Here in this example I am going to show you how to pretty print JSON in PHP program. I will use three different kind of JSON inputs to prettify them in the output. I am going to show you how…

Table of Contents Introduction Prerequisites Project Setup MySQL Table Application Properties Entity Class Repository Interface Service Class REST Controller Spring Boot Main Class Testing Hazelcast Caching Java Config for Hazelcast Source Code Introduction In this tutorial I am going to show you an example on caching using hazelcast in Spring Boot REST APIs. The cache or caching mechanism is used…

Infrastructure as Code or IaC, as the name indicates, mainly relies on on perceiving infrastructure in the same way as any code which is why it is commonly referred to as programmable infrastructure. It simply provides means to define and manage the IT infrastructure by using configuration files. The IaC concept came into prominence because of the limitations associated with…

Table of Contents Introduction Prerequisites Project Setup Protect PDF using Password Testing Encrypted PDF Files Source Code Introduction This example is going to show you how to make pdf files password protected using Java programming language. Many applications require dynamic generation of PDF documents for reporting purpose, such as, generating statements for customers, readers buying online specific chapters of a…

Table of Contents Introduction Why do you want to connect to multiple database Prerequisites Project Setup Application Properties DataSource Configurations DAO Class Source Code Introduction Here I am going to show you how to connect to Oracle data source using JDBC LDAP URL. I am going to create multiple data sources for connecting to multiple Oracle databases using Spring Boot…

Table of Contents Introduction What Is Dead Letter Queue Prerequisites Project Setup Application Properties Custom Exception Producer or Sender Consumer or Receiver Config Class Spring Boot Main Class Testing RabbitMQ Dead Letter Queue Source Code Introduction In this example I am going to show you how to retry the failed messages in RabbitMQ message broker. So, here I am going…

Table of Contents Introduction Prerequisites Angular Project Settings Gradle Properties Spring Boot Project Build App Testing Angular Spring Boot Integration Source Code Introduction In this tutorial I will show you how to integrate Angular into Spring Boot using Gradle build tool. So, let’s say you have two different projects – Angular application and Spring Boot application and you do not…

Table of Contents Introduction Prerequisites Angular App In Existing Folder Introduction In this example I am going to tell you how to create Angular project in existing folder. So, when you create a new Angular application using ng new angular-app command, where angular-app is the application’s or project’s name, then a new folder angular-app gets created. What if you need…

Table of Contents Introduction Prerequisites Project Setup Inheritance/Override Testing The Application Source Code Introduction In this example I am going to show you how to inherit values from application.properties into different environments. So, if you have an application.properties file under class path folder src/main/resources and if you have different environment specific application-{env}.properties files, then you csan inherit key/value pairs from application.properties file. Even you can override the inherited key/value…