ClassCastException: org.springframework.boot.context.event.ApplicationFailedEvent cannot be cast to org.springframework.boot.web.context.WebServerInitializedEvent

[deki]

Using Spring Boot 2.0.0.M3 a ClassCastException is thrown when the Tomcat cannot start properly (e.g. when BeanCreationException is thrown):

2017-07-31 10:15:59.193  WARN 20633 --- [           main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.context.ApplicationContextException: Unable to start web server; nested exception is org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat
2017-07-31 10:15:59.196  WARN 20633 --- [           main] o.s.b.c.e.EventPublishingRunListener     : Error calling ApplicationEventListener

java.lang.ClassCastException: org.springframework.boot.context.event.ApplicationFailedEvent cannot be cast to org.springframework.boot.web.context.WebServerInitializedEvent
        at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:159) [spring-context-5.0.0.RC3.jar:5.0.0.RC3]
        at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139) [spring-context-5.0.0.RC3.jar:5.0.0.RC3]
        at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:127) [spring-context-5.0.0.RC3.jar:5.0.0.RC3]
        at org.springframework.boot.context.event.EventPublishingRunListener.finished(EventPublishingRunListener.java:114) [spring-boot-2.0.0.M3.jar:2.0.0.M3]
        at org.springframework.boot.SpringApplicationRunListeners.callFinishedListener(SpringApplicationRunListeners.java:79) [spring-boot-2.0.0.M3.jar:2.0.0.M3]
        at org.springframework.boot.SpringApplicationRunListeners.finished(SpringApplicationRunListeners.java:72) [spring-boot-2.0.0.M3.jar:2.0.0.M3]
        at org.springframework.boot.SpringApplication.handleRunFailure(SpringApplication.java:803) [spring-boot-2.0.0.M3.jar:2.0.0.M3]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:338) [spring-boot-2.0.0.M3.jar:2.0.0.M3]
        at org.springframework.boot.test.context.SpringBootContextLoader.loadContext(SpringBootContextLoader.java:138) [spring-boot-test-2.0.0.M3.jar:2.0.0.M3]
        at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:99) [spring-test-5.0.0.RC3.jar:5.0.0.RC3]
        at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:117) [spring-test-5.0.0.RC3.jar:5.0.0.RC3]
        at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:107) [spring-test-5.0.0.RC3.jar:5.0.0.RC3]
        at org.springframework.boot.test.autoconfigure.SpringBootDependencyInjectionTestExecutionListener.outputConditionEvaluationReport(SpringBootDependencyInjectionTestExecutionListener.java:54) [spring-boot-test-autoconfigure-2.0.0.M3.jar:2.0.0.M3]
        at org.springframework.boot.test.autoconfigure.SpringBootDependencyInjectionTestExecutionListener.prepareTestInstance(SpringBootDependencyInjectionTestExecutionListener.java:47) [spring-boot-test-autoconfigure-2.0.0.M3.jar:2.0.0.M3]
        at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:242) [spring-test-5.0.0.RC3.jar:5.0.0.RC3]
        at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:227) [spring-test-5.0.0.RC3.jar:5.0.0.RC3]
        at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:289) [spring-test-5.0.0.RC3.jar:5.0.0.RC3]
        at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) [junit-4.12.jar:4.12]
        at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:291) [spring-test-5.0.0.RC3.jar:5.0.0.RC3]
        at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:246) [spring-test-5.0.0.RC3.jar:5.0.0.RC3]
        at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97) [spring-test-5.0.0.RC3.jar:5.0.0.RC3]
        at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) [junit-4.12.jar:4.12]
        at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) [junit-4.12.jar:4.12]
        at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) [junit-4.12.jar:4.12]
        at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) [junit-4.12.jar:4.12]
        at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) [junit-4.12.jar:4.12]
        at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) [spring-test-5.0.0.RC3.jar:5.0.0.RC3]
        at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70) [spring-test-5.0.0.RC3.jar:5.0.0.RC3]
        at org.junit.runners.ParentRunner.run(ParentRunner.java:363) [junit-4.12.jar:4.12]
        at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190) [spring-test-5.0.0.RC3.jar:5.0.0.RC3]
        at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:365) [surefire-junit4-2.20.jar:2.20]
        at org.apache.maven.surefire.junit4.JUnit4Provider.executeWithRerun(JUnit4Provider.java:272) [surefire-junit4-2.20.jar:2.20]
        at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:236) [surefire-junit4-2.20.jar:2.20]
        at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:159) [surefire-junit4-2.20.jar:2.20]
        at org.apache.maven.surefire.booter.ForkedBooter.invokeProviderInSameClassLoader(ForkedBooter.java:386) [surefire-booter-2.20.jar:2.20]
        at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:323) [surefire-booter-2.20.jar:2.20]
        at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:143) [surefire-booter-2.20.jar:2.20]

[philwebb]

Thanks for the issue report. This is probably related to recent updates that converted anonymous inner classes to lambdas. I think the underlying problem is a framework bug and I've raised SPR-15838 for them to look at.