Avoid reinitializing dispatcher servlet on refresh

[frhack]

Problem

The CAS configuration refresh listener eagerly resolves application context beans after refresh, but it also special-cases the dispatcherServlet bean and manually calls DispatcherServlet.init().

That call can run outside the servlet container lifecycle, where no ServletConfig is available. This may surface as a NullPointerException during refresh.

This was observed downstream in Apache Syncope WA:
https://issues.apache.org/jira/browse/SYNCOPE-1758

Root Cause

DefaultCasConfigurationEventListener#initializeBeansEagerly() currently:

• checks for dispatcherServlet
• retrieves DispatcherServlet.class
• sets the application context
• calls servlet.init()

The refresh listener should eagerly resolve beans as needed, but it should not manually initialize Spring MVC's DispatcherServlet. The servlet container/Spring Boot web lifecycle should own that initialization.

Changes

This removes the special-case reinitialization of Spring's DispatcherServlet from the CAS configuration refresh listener.

The listener still eagerly resolves all beans after refresh, but it no longer calls DispatcherServlet.init() manually.

References

• Apache Syncope downstream issue: https://issues.apache.org/jira/browse/SYNCOPE-1758

Checklist

• Brief description of changes applied
• Test cases for modified changes
• Pull request targets master
• Possible limitations or side effects documented
• Related issue referenced

Tests

• JAVA_HOME=/tmp/jdk25 ../../gradlew --no-daemon testCasConfiguration --tests org.apereo.cas.support.events.listener.CasConfigurationEventListenerTests

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