Java: SpringBoot3 - Unable to load Context

[tippexs]

On Unit 1.29.1 - Java17 - Docker eclipse-temurin:17-jdk-jammy

It is not possible to load a SpringBoot application version >=3.0. Unit did not crash. It simply isn't loading the Spring Application context. The log initially shows:

2023/05/06 01:34:53 [info] 1#1 unit 1.30.0 started
2023/05/06 01:34:53 [info] 76#76 discovery started
2023/05/06 01:34:53 [notice] 76#76 module: java 17.0.7 "/usr/lib/unit/modules/java.unit.so"
2023/05/06 01:34:53 [info] 1#1 controller started
2023/05/06 01:34:53 [notice] 1#1 process 76 exited with code 0
2023/05/06 01:34:53 [info] 78#78 router started
2023/05/06 01:34:53 [info] 78#78 OpenSSL 3.0.2 15 Mar 2022, 30000020
2023/05/06 01:34:53 [info] 79#79 "java" prototype started
2023/05/06 01:34:53 [info] 80#80 "java" application started

Sending request to the HelloWorldController which should answer with a nice Hello from Spring on Unit! is displaying a directory index like

t.stark@C02FN35FMD6R ~/w/u/p/docker (master)> curl -v localhost:8090
*   Trying 127.0.0.1:8090...
* Connected to localhost (127.0.0.1) port 8090 (#0)
> GET / HTTP/1.1
> Host: localhost:8090
> User-Agent: curl/7.79.1
> Accept: */*
>
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< Last-Modified: Sat, 06 May 2023 01:34:53 GMT
< Server: Unit/1.30.0
< Date: Sat, 06 May 2023 02:59:28 GMT
< Transfer-Encoding: chunked
<
<a href="WEB-INF">WEB-INF</a><br>
<a href="org">org</a><br>
<a href="META-INF">META-INF</a><br>
* Connection #0 to host localhost left intact

Starting unitd in debug mode shows the reason:

2023/05/06 02:45:12.831 [debug] 0#573 [unit] Context.wsSession.test: Endpoint instance registration failed
2023/05/06 02:45:13.379 [debug] 0#573 [unit] Context.loadInitializer: initializer: nginx.unit.websocket.server.WsSci
2023/05/06 02:45:13.384 [debug] 0#573 [unit] Context.loadInitializer: find handles: javax.websocket.server.ServerEndpoint
2023/05/06 02:45:13.385 [debug] 0#573 [unit] Context.loadInitializer: find handles: javax.websocket.server.ServerApplicationConfig
2023/05/06 02:45:13.385 [debug] 0#573 [unit] Context.loadInitializer: find handles: javax.websocket.Endpoint
2023/05/06 02:45:13.385 [debug] 0#573 [unit] Context.loadInitializer: no handles implementations
2023/05/06 02:45:13.386 [debug] 0#573 [unit] Context.load initializer(s)
2023/05/06 02:45:13.424 [debug] 0#573 [unit] Context.loadInitializer: initializer: org.apache.jasper.servlet.JasperInitializer
2023/05/06 02:45:13.424 [debug] 0#573 [unit] Context.loadInitializer: no HandlesTypes annotation
2023/05/06 02:45:13.428 [debug] 0#573 [unit] Context.URLPattern: '*.jsp' is a suffix pattern
2023/05/06 02:45:13.429 [debug] 0#573 [unit] Context.URLPattern: '*.jspx' is a suffix pattern

As Spring >= requires Tomcat10 with Servlet 5 it is not longer compatible with Units Servlet Implementation. Looking at the Changes from Apache Tomcat 8 to 10 shows that they moved from javax to jakarta.

It would be necessary to implement a new Servlet Spec to be able to load the Context of the newer generation of Spring Boot applications for example.

Please consider this issue as documentation only - we are not in a hurry to fix this for now. I just wanted to find a place to document my findings.

An application to reproduce is attached.

spring3-0.0.1-SNAPSHOT.war.zip

The unit configuration

{
  "listeners": {
    "*:80": {
      "pass": "applications/java"
    }
  },

  "applications": {
    "java": {
      "type": "java",
      "webapp": "spring3-0.0.1-SNAPSHOT.war",
      "working_directory": "/var/www/"
    }
  }
}