Tonight Only: Join the AppLand Team at the Boston Java Meetup!

Posted 30 Aug 2021 by Petr Dvorak

We’re excited to host a hands-on, online workshop tonight at 6 pm EDT for the Boston Java Meetup Group! Come join us, all are welcome and we’d love to meet you 😊

We’ll be demoing how to use a free and open source tool to highlight a design flaw in a simple Spring application. We’ll also show how to use the tool to analyze your own projects, so you can follow along using the same simple application we’ll be using, or use your own Java-based app.

Here’s everything you’ll need to join us and get the most out of the event…

For all the logistical details and how to register (for free!), click here.

Prerequisites

JDK 8 and newer
macOS, Linux or Windows are all fine
Supported IDE: IntelliJ 2021.1 or newer, or VSCode with Java extensions
git client, basic familiarity with git
Node.js installed
GitHub or GitLab account

Instructions for installing and using AppMap for Java

Step 1: Clone, build and run the Spring Petclinic Application

Clone the Petclinic git repository to a local folder

git clone https://github.com/spring-projects/spring-petclinic.git
cd spring-petclinic

Build locally with Maven
- mvnw clean install (Windows)
- ./mvnw clean install (macOS, Linux)
Start the app and open the web UI
- java -jar target/*.jar
- Open http://localhost:8080
Stop the app with CTRL+C

Step 2: Install AppMap for IntelliJ or VSCode

Open the PetClinic project in your IDE
Install AppMap from the marketplace
Use this command to install the appmap-java agent for this project
```
  npx @appland/appmap install
```

Step 3: Record and open AppMaps from tests

Run tests with Maven
- mvnw test (Windows)
- ./mvnw test (macOS, Linux)
View recorded AppMaps in your IDE:
- In IntelliJ
- In VSCode

Step 4: Record AppMaps with remote recording

The AppMap agent can record all running application code. In this step, we’ll instrument the application server and record your application’s behavior as it runs. Here’s how it’ll happen:

Configure and start the application with remote recording
- Download appmap-1.5.0.jar
- Start the application with the appmap-1.5.0.jar javaagent:
```
java -javaagent:appmap-1.5.0.jar -jar target/*.jar 
```
Record an AppMap
- Start AppMap recording in your IDE
  - IntelliJ: Menu Tools -> AppMap -> Start AppMap Recording
  - VSCode: SHIFT+COMMAND+P AppMap: Start remote recording
- Find and view owner in the PetClinic application
- Stop and save AppMap in your IDE
  - IntelliJ: Menu Tools -> AppMap -> Stop AppMap Recording
  - VSCode: SHIFT+COMMAND+P AppMap: Stop remote recording
Inspect the recorded AppMap
- HTTP requests
- Function calls
- SQL commands

Step 5: Record and inspect the behavior of the Spring framework

Configure AppMaps for shallow recording of the Spring framework. Update the appmap.yml file in the project root folder to include this path:

 - path: org.springframework.web
   shallow: true
   exclude:
   - org.springframework.web.filter.OncePerRequestFilter
   - org.springframework.web.context.request.RequestContextHolder
   - org.springframework.web.context
   - org.springframework.web.servlet.resource.ResourceUrlEncodingFilter

Make a new remote recording
- Start AppMap recording in your IDE
- Find and view owner in the PetClinic app
- Stop and save AppMap
Inspect the Spring framework events in the AppMap
- See how OwnerController is called from the framework

Step 6: Find N+1 anti-pattern with AppMaps

Find and fix N+1 SQL antipattern in the Pet Clinic app
- View the anti-pattern in a recorded AppMap
  - Find and open a ‘should find vets’ AppMap recorded from a test
  - View the SQL commands
- Find the bug and fix the code (here is a hint)
- Re-record the AppMap with the fix in place and compare it with the “before” AppMap

Step 7: Record AppMaps of your own application

Set Up AppMap for your application
Fine-tune the AppMap configuration for your app
Record and open AppMaps