spring MVC3 errors Could not instantiate bean class [java.util.List]: Specified class is an interface Occasional

Question

I am using spring MVC3, I found code like below:

@Controller
class IndexController
{
    @ModelAttribute("allTags")
    public List<ArticleTag> allTags()
    {
        return Collections.emptyList();
    }
}

Sometimes errors with message

(Not always)

SEVERE: Servlet.service() for servlet [appServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [java.util.List]: Specified class is an interface] with root cause
org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [java.util.List]: Specified class is an interface
        at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:101)
        at org.springframework.web.method.annotation.ModelAttributeMethodProcessor.createAttribute(ModelAttributeMethodProcessor.java:132)
        at org.springframework.web.servlet.mvc.method.annotation.ServletModelAttributeMethodProcessor.createAttribute(ServletModelAttributeMethodProcessor.java:81)
        at org.springframework.web.method.annotation.ModelAttributeMethodProcessor.resolveArgument(ModelAttributeMethodProcessor.java:103)
        at org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:75)
        at org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:156)
        at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:117)
        at org.springframework.web.method.annotation.ModelFactory.invokeModelAttributeMethods(ModelFactory.java:123)
        at org.springframework.web.method.annotation.ModelFactory.initModel(ModelFactory.java:97)
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:614)
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:578)
        at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
        at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:923)
        at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:852)
        at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
        at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:778)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)

Someone Says, List is a interface, plz use ArrayList or LinkedList instead

But, My Question is, Why the code above is not always eror?

When the error above occured, not matter how to refresh the page, error continues, nevery disappear！But, If you restart tomcat, you have a good opportunity to walk through this error!If no error like above occur,it never occurs util next tomcat restart!

Same as @ModelAttribute with type int or Integer, it will very likely error, but on some host, It never occurs

Answer 1

Change the code as below

public ArticleTag allTags()

For more information, please refer to below link

[ http://forum.spring.io/forum/spring-projects/data/nosql/724397-mapping-exception-with-mongodb-aggregation-framework][1]

Also refer to Mongo Issue fixed

[ https://jira.spring.io/browse/DATAMONGO-229]