This looks really cool! https://grails.slack.com/archives/C07LCNWHG/p1727404354990749 I tried out the git repo and the create-controller command works, but it does not seem that other code changes (e.g. modifying a controller or service) are hot-swapped. I see messages about from the hotswap agent "Spring plugin initialized" after making a code change, but when I reload the page the change isn't reflected. Would this sort of change be expected to be updated by the hotswap agent? I'm also curious what the "Reloading active: true" means in the "Application Status" menu? I noticed that if I added

developmentOnly("org.springframework.boot:spring-boot-devtools")

to the build.gradle dependencies it changes from false->true, but I haven't been able to spot any reloading happening. Does the application have to be run through IntelliJ to leverage this kind of reloading? What kind of changes can be reloaded?

You have to make sure you run a specific jdk and install the hot swap jar in a specific place .

Thanks @davydotcom! I thought the sdkman commands/GitHub readme from the video did that?

Yes it is

Thank you!

I did demo a controller Method reloading I was pretty sure. I know I did it before I made the video . And a service reload

That looks so cool! I'm a bit stumped why it's not working on my end. I tried running on my windows box, and noticed you're running on mac so I tried it on my mac laptop too... I see the hotswap jar under ~/.sdkman/candidates/java/21.0.4-jbr/lib/hotswap/hotswap-agent.jar the java -version is the same as yours (OpenJDK 64-Bit Server VM JBR-21.0.4+8-569.1-jcef (build 21.0.4+8-b569.1, mixed mode, sharing)) If I

ps aux | grep java

after launching the app I see the JVM arguments and it also appears to be picking up the hotswap agent JAR on launch I see a bunch of messages about "not eligible for BeanPostProcessors" as well as errors from the hotswap agent XmlBeanDefinitionScannerAgent about being unable to convert .xml to classPath path. The log messages from your video go by too quickly for me to see if you get these too. Would you mind sharing?

I need to check Scott’s sample repo , he may be missing something from my text

By a stroke of luck I got it working: when I re-ran I started getting HibernateException: No Session found for current thread This lead me to : https://stackoverflow.com/questions/64104951/has-anyone-had-success-with-grails-4-java-11-and-using-dcevm-for-hotswapping-d which recommends disabling the hibernate plugin. I noticed that there is a hibernate plugin getting initialized. I modified hotswap-properties to disable both plugins:

disabledPlugins=Hibernate,HibernateJakarta

I also needed to move the properties file from src/main to src/main/resources

Micronaut being the parent context prevented hot swap from working before

Just out of curiosity, did you have the hibernate Jakarta exclusion, or is that something specific to my machine?

You have to exclude hibernate yes

Thank you!