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Editorial Team
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Asked: 2026-05-31T06:51:22+00:00

Please forgive if i use terminology wrong, but i’m new to java-web development and

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Please forgive if i use terminology wrong, but i’m new to java-web development and Spring.
Correct my assumptions, if i’m wrong.

I want to create a WebApp, that uses Vaadin for UI and Spring MVC for RESTful Web-Services.
So, i think, I need 2 Servlets.
One for serving Vaadin and one for serving Spring MVC.

I have some generic dao-beans, which are used by both servlets, so i thought, that i could use Spring, with @Autowired annotation to inject those @Repository and @Component – tagged beans into the MVC and the Vaadin-“(App|Servlet)”. (Discovered through springs component-scan – feature)

But i can’t get it working.
The Spring-MVC-App – works. I’ve annotated all @Controllers and all things are @Autowired automaticly.

But in Vaadin i always get:

SCHWERWIEGEND: Servlet.service() for servlet [hello] in context with path [/pliste] threw exception [javax.servlet.ServletException: failed to acquire new instance of class net.d21.pliste.HelloWorld] with root cause
org.springframework.beans.factory.NoSuchBeanDefinitionException: No unique bean of type [net.d21.pliste.HelloWorld] is defined: expected single bean but found 0:

I think my basic question is, how to inject general dependencies into 2 different servlets? (In my case it’s Vaadin and MVC, but i think it’s replaceable).

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1 Answer

  1. Editorial Team

    A typical Spring webapp has a 2-level hierarchy of application contexts:

    • Root application context loaded by ContextLoaderListener, its default config file is applicationContext.xml. This context contains common beans that can be used by all servlets, filters, etc.

    • Servlet-specific application contexts. Their default config locations are ${serlvet-name}-servlet.xml. These contexts contain beans specific to particualr servlets.

    So, in your case you need to declare common beans in applicationContext.xml and servlet-specific beans (for example, controllers for Spring MVC) in servlet-specific contexts.

    Note that if you use <component-scan> you need to avoid duplication of beans in different contexts, either by using different base packages or by filtering them by annotations.

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