Cannot run static enhancement of OpenJPA entities with Spring Boot

mvn package fails at the openjpa-maven-plugin:enhance stage when I try to enhance my JPA entities in a Spring Boot app.

There's a long error description

enhance failed: MetaDataFactory could not be configured (conf.newMetaDataFactoryInstance() returned null).

no configuration properties were found.

It lists some reasons:

1. Ensure that you have a META-INF/persistence.xml file, that it is available in your classpath

   • I'm using spring-data-jpa with Java config, and there's no
     persistence.xml. Is it possible to do openjpa:enhance without
     it?

2. Ensure the properties file you are using for configuration is available. If you are using Ant, please see the or attributes of the task's nested element.

   • I specify all the OpenJPA properties in a subclass of Spring's org.springframework.boot.autoconfigure.orm.jpa.JpaBaseConfiguration - see the class below. This is probably what I need to change, but how? And where to specify the properties file so openjpa-maven-plugin can find it?

3. This can also occur if your OpenJPA distribution jars are corrupt, or if your security policy is overly strict.

   • ruled out - I checked redownloaded the OpenJPA jars with checksumPolicy=fail so that's proof that they're not corrupted, plus I'm not using any security policy at this level.

pom.xml

        <plugin>
            <groupId>org.apache.openjpa</groupId>
            <artifactId>openjpa-maven-plugin</artifactId>
            <configuration>
                <includes>**/entity/*.class</includes>
                <addDefaultConstructor>true</addDefaultConstructor>
                <enforcePropertyRestrictions>true</enforcePropertyRestrictions>
            </configuration>
            <executions>
                <execution>
                    <id>enhancer</id>
                    <phase>process-classes</phase>
                    <goals>
                        <goal>enhance</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>

openjpa-maven-plugin error

[INFO] --- openjpa-maven-plugin:2.4.1:enhance (enhancer) @ project-x ---
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 16.707 s
[INFO] Finished at: 2016-12-15T09:51:36+00:00
[INFO] Final Memory: 44M/359M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.openjpa:openjpa-maven-plugin:2.4.1:enhance 
(enhancer) on project x: Execution enhancer of goal org.apache.openjpa:openjpa-maven-plugin:2.4.1:enhance 
failed: MetaDataFactory could not be configured (conf.newMetaDataFactoryInstance()
returned null). This might mean that no configuration properties were found. Ensure that 
you have a META-INF/persistence.xml file, that it is available in your classpath, or that
the properties file you are using for configuration is available. If you are using Ant,
please see the <properties> or <propertiesFile> attributes of the task's nested <config>
element. This can also occur if your OpenJPA distribution jars are corrupt, or if your
security policy is overly strict. -> [Help 1]

Subclass of JpaBaseConfiguration

@Import({
        LdapConfig.class,
        SecurityConfig.class,
        PropertySpringConfig.class
})
@SpringBootApplication
@EnableJpaRepositories(basePackages = {"com.adam.x.repository"})
@EntityScan(basePackages = {"com.adam.x.entity"})
public class MyWebApplication extends JpaBaseConfiguration {

    public static void main(String[] args) {
        SpringApplication.run(MyWebApplication.class, args);
    }

    protected MyWebApplication(
            DataSource dataSource,
            JpaProperties properties,
            ObjectProvider<JtaTransactionManager> jtaTransactionManagerProvider) {
        super(dataSource, properties, jtaTransactionManagerProvider);
    }

    @Override
    protected AbstractJpaVendorAdapter createJpaVendorAdapter() {
        OpenJpaVendorAdapter jpaVendorAdapter = new OpenJpaVendorAdapter();
        jpaVendorAdapter.setShowSql(true);
        return jpaVendorAdapter;

    }

    @Override
    protected Map<String, Object> getVendorProperties() {
        HashMap<String, Object> map = new HashMap<String, Object>();
        map.put("openjpa.Log", "DefaultLevel=TRACE, Tool=INFO, SQL=TRACE, Runtime=TRACE");
        map.put("openjpa.jdbc.MappingDefaults", "IndexLogicalForeignKeys=false,IndexDiscriminator=false");
//        map.put("openjpa.jdbc.SynchronizeMappings", "buildSchema(ForeignKeys=true)");
        map.put("openjpa.RuntimeUnenhancedClasses", "supported");
//        map.put("openjpa.DynamicEnhancementAgent", "true");
//        map.put("openjpa.weaving", "false");
        return map;
    }


}

This answer here sorted it out for me.

The maven plugin needs a persistence.xml to work, which is slightly not DRY because I have to remember to list any new entity beans in there, but I figured it's a small price.

OpenJPA and Spring-boot configuration