Try adding this dependency to your kotlin-maven-plugin
kotlin-maven-allopen
Your pom will look somewhat like this after adding:
<plugin>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-maven-plugin</artifactId>
<version>${kotlin.version}</version>
<executions>
<execution>
<id>compile</id>
<phase>compile</phase>
<goals>
<goal>compile</goal>
</goals>
</execution>
<execution>
<id>test-compile</id>
<phase>test-compile</phase>
<goals>
<goal>test-compile</goal>
</goals>
</execution>
</executions>
<configuration>
<args>
<arg>-Xjsr305=strict</arg>
</args>
<compilerPlugins>
<plugin>spring</plugin>
</compilerPlugins>
<jvmTarget>1.8</jvmTarget>
</configuration>
<dependencies>
<dependency>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-maven-allopen</artifactId>
<version>${kotlin.version}</version>
</dependency>
</dependencies>
</plugin>
What a mess. I don't remember where I found this but I had to add the following to get M2Eclipse to be happy. Even more sad is that it isn't exactly easy to understand why this tag is needed.
<!-- language: xml -->
<build>
... various plugins ...
<pluginManagement>
<plugins>
<!--This plugin's configuration is used to store Eclipse
m2e settings only. It has no influence on the Maven build itself. -->
<plugin>
<groupId>org.eclipse.m2e</groupId>
<artifactId>lifecycle-mapping</artifactId>
<version>1.0.0</version>
<configuration>
<lifecycleMappingMetadata>
<pluginExecutions>
<pluginExecution>
<pluginExecutionFilter>
<groupId>org.codehaus.mojo</groupId>
<artifactId>aspectj-maven-plugin</artifactId>
<versionRange>[1.0,)</versionRange>
<goals>
<goal>test-compile</goal>
<goal>compile</goal>
</goals>
</pluginExecutionFilter>
<action>
<execute />
</action>
</pluginExecution>
</pluginExecutions>
</lifecycleMappingMetadata>
</configuration>
</plugin>
</plugins>
</pluginManagement>
</build>
There were a number of other issues with the M2Eclipse plug-in that simply didn't work with Spring Data. In the end I disabled M2Eclipse in favor of the [Apache Eclipse plug-in][1].
[1]: http://maven.apache.org/plugins/maven-eclipse-plugin/
