SivaLabs

RabbitMQ is one of the popular message broker solutions and provides client libraries to be used from various programming languages including Java, Scala, .NET, Go, Python, Ruby, PHP etc. In this tutorial, we will learn how to use RabbitMQ message broker to send and receive messages from a SpringBoot application. We will also look at how to send messages as JSON payloads and how to deal with errors using Dead Letter Queues (DLQ).

In web applications, user session management is very crucial for managing user state. In this article, we are going to learn about what are the approaches we have been following to manage user sessions in a clustered environment and how we can use Spring Session to implement it in a much simpler and more scalable way. Typically in production environments, we will have multiple server nodes with a load balancer in front of them and all the client traffic will be coming through the load balancer to one of the server nodes.

In this article we are going to learn how we can use Travis CI for Continuous Integration and Continuous Deployment (CI/CD) of a SpringBoot application. We will learn how to run maven build goals, perform test coverage validation using JaCoCo plugin, Code Quality checks using SonarCloud, build Docker image and push it to DockerHub and finally deploy it to Heroku. The source code for this article is at https://github.com/sivaprasadreddy/jblogger

If you are working on Spring Boot then you most probably aware of Spring Initializer (http://start.spring.io) which is an online spring boot application generator. You can select the starters that you want to use and then generate the application. If you notice that there is no SELECT ALL option to select all the starters. Who would do that insane thing of selecting all the starters for an application??!!??? But, i would like to have the SELECT ALL option for one single reason:

Problem In the previous article Introduction to Spring Cloud Config Server we have seen how to use Spring Cloud Config Server. But, the problem is to reload the config changes in Config Client applications we need to trigger /refresh endpoint manually. This is not practical and viable if you have large number of applications. Solution Spring Cloud Bus module can be used to link multiple applications with a message broker and we can broadcast configuration changes.

Problem SpringBoot provides lot of flexibility in externalizing configuration properties via properties or YAML files. We can also configure properties for each environment (dev, qa, prod etc) separately using profile specific configuration files such as application.properties, application-dev.properties, application-prod.properties etc. But once the application is started we can not update the properties at runtime. If we change the properties we need to restart the application to use the updated configuration properties.

We can use Intellij IDEA Community Edition for working with SpringBoot applications as we don’t need support for configuring servers like Tomcat, Wildlfy etc and can simply run the applications by running main() method. However, there is no provision in Intellij IDEA Community Edition to create SpringBoot application directly, the way it supports in Ultimate Edition. We can go to http://start.spring.io/ and generate the project and then import into our IDE.

I would like to let you know that I have updated/added the following sections to my SpringBoot : Learn By Example book. Additions to existing chapters: Working with Multiple Databases Exposing JPA entities with bi-directional references through RESTful services In some of our applications we need to work with multiple databases. For example, we may have a primary database and a reporting database where most the application uses primary database and the application reports will be generated out of reporting database data.

I am happy to announce that my new book SpringBoot : Learn By Example got published today on Leanpub. What is SpringBoot? Spring is one of the most popular Java frameworks out there to build web and enterprise application. Spring supports variety of configuration approaches (XML, Annotations, JavaConfig etc) and properly configuring Spring applications become a bit tedious and repetitive process. To avoid these problems Spring team introduced SpringBoot to address the complexity of configuring Spring application.

SpringBoot provides lot of starter modules to get up and running quickly. SpringBoot’s auto-configure mechanism takes care of configuring SpringBeans on our behalf based on various criteria. In addition to the springboot starters that comes out-of-the-box provided by Core Spring Team, we can also create our own starter modules. In this post we will look into how to create a custom SpringBoot starter. To demonstrate it we are going to create twitter4j-spring-boot-starter which will auto-configure Twitter4J beans.