How to use a Vaadin 14 Application as a Dependency?

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 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.