EnhanceRequireObjectCache Cast Exception - Skywalking

Problem

When you start your application with the skywalking agent, you may find this exception in your agent log which means that EnhanceRequireObjectCache cannot be casted to EnhanceRequireObjectCache. For example:

java

ERROR 2018-05-07 21:31:24 InstMethodsInter :  class[class org.springframework.web.method.HandlerMethod] after method[getBean] intercept failure
java.lang.ClassCastException: org.apache.skywalking.apm.plugin.spring.mvc.commons.EnhanceRequireObjectCache cannot be cast to org.apache.skywalking.apm.plugin.spring.mvc.commons.EnhanceRequireObjectCache
	at org.apache.skywalking.apm.plugin.spring.mvc.commons.interceptor.GetBeanInterceptor.afterMethod(GetBeanInterceptor.java:45)
	at org.apache.skywalking.apm.agent.core.plugin.interceptor.enhance.InstMethodsInter.intercept(InstMethodsInter.java:105)
	at org.springframework.web.method.HandlerMethod.getBean(HandlerMethod.java)
	at org.springframework.web.servlet.handler.AbstractHandlerMethodExceptionResolver.shouldApplyTo(AbstractHandlerMethodExceptionResolver.java:47)
	at org.springframework.web.servlet.handler.AbstractHandlerExceptionResolver.resolveException(AbstractHandlerExceptionResolver.java:131)
	at org.springframework.web.servlet.handler.HandlerExceptionResolverComposite.resolveException(HandlerExceptionResolverComposite.java:76)
	...

Reason

This exception may be caused by hot deployment tools (spring-boot-devtool) or otherwise, which changes the classloader in runtime.

Resolution

This error does not occur under the production environment, since developer tools are automatically disabled: See spring-boot-devtools.
If you would like to debug in your development environment as usual, you should temporarily remove such hot deployment package in your lib path.