How to use a Vaadin 14 Application as a Dependency? - spring

Question

I try to use a Vaadin 14 application as a dependency for a Spring Boot Project. The Vaadin project uses a single View and an embedded Tomcat and runs fine. pom.xml of the project:
...
<groupId>my.package</groupId>
<artifactId>my-artifact</artifactId>
...
...
<dependencyManagement>
<dependencies>
<dependency>
<groupId>com.vaadin</groupId>
<artifactId>vaadin-bom</artifactId>
<version>${vaadin.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
...
<dependency>
<groupId>com.vaadin</groupId>
<artifactId>vaadin-spring-boot-starter</artifactId>
<exclusions>
<!-- Excluding so that webjars are not included. -->
<exclusion>
<groupId>com.vaadin</groupId>
<artifactId>vaadin-core</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-validation</artifactId>
<version>2.6.6</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<version>2.6.6</version>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<version>2.6.6</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.vaadin</groupId>
<artifactId>vaadin-testbench</artifactId>
<scope>test</scope>
</dependency>
...
<build>
<defaultGoal>spring-boot:run</defaultGoal>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<!-- Clean build and startup time for Vaadin apps sometimes may exceed
the default Spring Boot's 30sec timeout. -->
<configuration>
<wait>500</wait>
<maxAttempts>240</maxAttempts>
</configuration>
<executions>
<execution>
<goals>
<goal>repackage</goal>
</goals>
<configuration>
<classifier>exec</classifier>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
...
So I basically tried to add a classifier to the spring-boot-maven-plugin of the application like stated here.
And when I run mvn install I get the two jars as I expect.
Now, I create a new Spring Application and import the dependency in the pom.xml:
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
<version>2.7.3</version>
</dependency>
<dependency>
<groupId>my.package</groupId>
<artifactId>my-artifact</artifactId>
<version>1.0-SNAPSHOT</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
Now, when I try to run the app I get this error message:
Error starting Tomcat context. Exception: org.springframework.beans.factory.BeanCreationException. Message: Error creating bean with name 'formContentFilter' defined in class path resource [org/springframework/boot/autoconfigure/web/servlet/WebMvcAutoConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.boot.web.servlet.filter.OrderedFormContentFilter]: Factory method 'formContentFilter' threw exception; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.fasterxml.jackson.datatype.jsr310.JavaTimeModule]: Unresolvable class definition; nested exception is java.lang.NoClassDefFoundError: com/fasterxml/jackson/databind/ser/std/ToStringSerializerBase
Is it even possible to have a Vaadin project as a dependency? If yes, what I am missing - can someone help me out?

Answer 1

Spring Boot applications have a different JAR layout and cannot be used as dependencies.