Spring Boot is a great framework for building microservices and other production-grade applications. One of the benefits of using Spring Boot is that it comes with an embedded Tomcat server, which makes it easy to deploy your application as a standalone jar.
However, one of the drawbacks of using an embedded server is that it can be difficult to troubleshoot performance issues. In this article, we'll take a look at how to use VisualVM to profile a Spring Boot application.
VisualVM is a tool that provides a graphical interface for viewing detailed information about Java applications. It can be used to monitor and troubleshoot applications running on the JVM.
VisualVM is included in the Oracle JDK, so if you have the JDK installed, you already have VisualVM. If you don't have the JDK installed, you can download VisualVM from the Oracle website.
Now that we have VisualVM installed, let's take a look at how to use it to profile a Spring Boot application.
First, we need to start our Spring Boot application. We'll use the Spring PetClinic sample application for this example.
Once the application is up and running, we can open VisualVM and connect to the running application. To do this, click on the "File" menu and select "Add JMX Connection".
In the "Add JMX Connection" dialog, enter the host and port of the running application. The default host is "localhost" and the default port is "1099".
Click "OK" to connect to the running application.
Once VisualVM is connected to the running application, you should see the application in the "Applications" tab.
To start profiling the application, select the application in the "Applications" tab and click the "Profile" button.
In the "Profile Application" dialog, select the "CPU" profiling type and click "Start".
Once the profiling session has started, you can use VisualVM to view the thread activity, memory usage, and other information about the running application.
When you're finished profiling the application, you can stop the profiling session by selecting the "File" menu and selecting "Exit".
In this article, we've seen how to use VisualVM to profile a Spring Boot application. VisualVM is a powerful tool that can be used to troubleshoot performance issues in Spring Boot applications.