How to enable logging for a Datanucleus application based on Maven? - maven

Question

My question is pretty straightforward.
Given the following POM:
<build>
<plugins>
<plugin>
<groupId>org.datanucleus</groupId>
<artifactId>maven-datanucleus-plugin</artifactId>
<version>3.0.0-release</version>
<configuration>
<log4jConfiguration>${basedir}/src/main/resources/log4j.properties</log4jConfiguration>
<verbose>true</verbose>
<props>${basedir}/src/main/resources/datanucleus.properties</props>
</configuration>
<executions>
<execution>
<phase>compile</phase>
<goals>
<goal>enhance</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
<repositories>
<repository>
<id>DataNucleus_Repos2</id>
<name>DataNucleus Repository</name>
<url>http://www.datanucleus.org/downloads/maven2</url>
</repository>
<repository> <!-- Required for transaction-api transitive dep -->
<id>Java_Net_LEGACY</id>
<name>Java.Net legacy</name>
<url>http://download.java.net/maven/1/</url>
<layout>legacy</layout>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<id>DataNucleus_2</id>
<url>http://www.datanucleus.org/downloads/maven2/</url>
</pluginRepository>
</pluginRepositories>
<dependencies>
<dependency>
<groupId>org.datanucleus</groupId>
<artifactId>datanucleus-core</artifactId>
<scope>runtime</scope>
<version>3.0.2</version>
</dependency>
<dependency>
<groupId>org.datanucleus</groupId>
<artifactId>datanucleus-api-jdo</artifactId>
<version>3.0.2</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.16</version>
</dependency>
<dependency>
<groupId>org.datanucleus</groupId>
<artifactId>datanucleus-rdbms</artifactId>
<version>3.0.2</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.9</version>
</dependency>
<dependency>
<groupId>javax.jdo</groupId>
<artifactId>jdo-api</artifactId>
<version>3.0</version>
</dependency>
<dependency>
<groupId>org.apache.geronimo.specs</groupId>
<artifactId>geronimo-jpa_2.0_spec</artifactId>
<version>1.0</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.18</version>
</dependency>
</dependencies>
And given that I have the files log4j.properties and datanucleus.properties in their expected place, when I run
mvn compile
I get (taken from datanucleus.log file)
19:36:11,297 (main) ERROR [DataNucleus.Enhancer] - DataNucleus
Enhancer completed with an error. Please review the enhancer log for
full details. Some classes may have been enhanced but some caused
errors Error creating the MetaDataManager for API "JDO" :
org.datanucleus.exceptions.NucleusException: Error creating the
MetaDataManager for API "JDO" : at
org.datanucleus.NucleusContext.getMetaDataManager(NucleusContext.java:964)
at
org.datanucleus.enhancer.DataNucleusEnhancer.getMetaDataManager(DataNucleusEnhancer.java:261)
at
org.datanucleus.enhancer.DataNucleusEnhancer.getFileMetadataForInput(DataNucleusEnhancer.java:716)
at
org.datanucleus.enhancer.DataNucleusEnhancer.enhance(DataNucleusEnhancer.java:590)
at
org.datanucleus.enhancer.DataNucleusEnhancer.main(DataNucleusEnhancer.java:1390)
Caused by: java.lang.reflect.InvocationTargetException at
sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown
Source) at
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown
Source) at java.lang.reflect.Constructor.newInstance(Unknown Source)
at
org.datanucleus.plugin.NonManagedPluginRegistry.createExecutableExtension(NonManagedPluginRegistry.java:681)
at
org.datanucleus.plugin.PluginManager.createExecutableExtension(PluginManager.java:314)
at
org.datanucleus.NucleusContext.getMetaDataManager(NucleusContext.java:958)
... 4 more
Caused by: java.lang.NoSuchFieldError: supportsORM at
org.datanucleus.api.jdo.metadata.JDOMetaDataManager.(JDOMetaDataManager.java:142)
... 11 more
I would like to enable logging to see what queries are being done by my application.
A thing to note is that the enhancement works fine when removing log4j dependency from the POM. Of course, the log file doesn't get updated anymore, but the classes are enhanced.
Any idea related to the above behaviour will be greatly appreciated.

Answer 1

The documentation give a different look of the configuration for the plugin in particular in the executions:
<executions>
<execution>
<phase>process-classes</phase>
<goals>
<goal>enhance</goal>
</goals>
</execution>
</executions>
which might many problems. Furthermore you should remove the repository definitions from your pom, cause based on a short check all these dependencies are available via maven central. If you really need to configure the repositories you should use a repository manager instead.