spring-modulith-observability causes Kotlin bean properties to be initialized as null

[itanxiao]

When enabling spring-modulith-observability, Kotlin bean properties are unexpectedly initialized as null. For example, after enabling this module, properties such as hisHttpClient and medicalInstitutionCode are null. Disabling the module resolves the problem.

Expected behavior:

• Kotlin bean properties should be correctly initialized when observability is enabled.

Actual behavior:

• When spring-modulith-observability is enabled, the properties in the Kotlin bean are null as seen in the following screenshots.

Screenshots:

1. Bean initialization with null values:

2. CGLIB proxy details showing null for constructor-injected properties:

[itanxiao]

The version used is 1.2.3

[odrotbohm]

That's not unexpected regarding the class that you see being a proxy whose actual target will still have the proper dependencies wired. This should only be a problem if you try to access the fields directly. Method invocations, however, will pass the interceptor chain and ultimately trigger the method invocation on the target.

Can you clarify how a problem manifests from that, beyond you seeing the null fields in the debugger?

[itanxiao]

java.lang.NullPointerException: Parameter specified as non-null is null: method reqeust.MedicalInfoRequest.<init>, parameter medicalInstitutionCode

That's not unexpected regarding the class that you see being a proxy whose actual target will still have the proper dependencies wired. This should only be a problem if you try to access the fields directly. Method invocations, however, will pass the interceptor chain and ultimately trigger the method invocation on the target.

Can you clarify how a problem manifests from that, beyond you seeing the null fields in the debugger?

[odrotbohm]

Unfortunately few line screenshots are not that helpful in diagnosing the problem. Is there any chance you provide a minimal reproducer? Is anyone trying to access the field directly instead of calling a method passing the proxy?

[itanxiao]

Unfortunately few line screenshots are not that helpful in diagnosing the problem. Is there any chance you provide a minimal reproducer? Is anyone trying to access the field directly instead of calling a method passing the proxy?

test project

spring-modulith-test-main.zip

[odrotbohm]

$ git clone https://github.com/chenzhenjia/spring-modulith-test
$ cd spring-modulith-test
$ chmod +x ./gradlew
$ ./gradlew
BUILD SUCCESSFUL in 1m 30s
1 actionable task: 1 executed

How do I reproduce the problem?

[itanxiao]

$ git clone https://github.com/chenzhenjia/spring-modulith-test

$ cd spring-modulith-test

$ chmod +x ./gradlew

$ ./gradlew

BUILD SUCCESSFUL in 1m 30s

1 actionable task: 1 executed

How do I reproduce the problem?

Start the application and visit http://127.0.0.1:8080 to see the exception in the console.

[odrotbohm]

I am sorry, but I won't follow up unless you can properly prepare the project, including instructions what to do with the code to see the problem (what does "start the application" mean?). I ran the project (./gradlew). It leads to a successful build.

[itanxiao]

I am sorry, but I won't follow up unless you can properly prepare the project, including instructions what to do with the code to see the problem (what does "start the application" mean?). I ran the project (./gradlew). It leads to a successful build.

Try ./gradlew bootRun or ./gradlew :app bootRun to start the spring boot application

[odrotbohm]

For the former command, I get:

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':core:bootRun'.
> Failed to calculate the value of task ':core:bootRun' property 'mainClass'.
   > Main class name has not been configured and it could not be resolved from classpath /Users/odrotbohm/temp/spring-modulith-test/core/build/classes/kotlin/main

For the latter:

FAILURE: Build failed with an exception.

* What went wrong:
Cannot locate tasks that match ':app' as task 'app' not found in root project 'spring-modulith-test'.

[itanxiao]

For the former command, I get:

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':core:bootRun'.
> Failed to calculate the value of task ':core:bootRun' property 'mainClass'.
   > Main class name has not been configured and it could not be resolved from classpath /Users/odrotbohm/temp/spring-modulith-test/core/build/classes/kotlin/main

For the latter:

FAILURE: Build failed with an exception.

* What went wrong:
Cannot locate tasks that match ':app' as task 'app' not found in root project 'spring-modulith-test'.

My mistake, I should have used ./gradlew :app:bootRun