Maven Aspectj plugin calls the JPA model generator again

Question

I have a Maven project where I generate the JPA metamodel using the Hibernate metamodel generator.

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>xxx</groupId>
        <artifactId>xxx</artifactId>
        <version>1.0.0-SNAPSHOT</version>
    </parent>
    <artifactId>xxx</artifactId>
    <dependencies>
        <dependency>
            <groupId>org.hibernate.javax.persistence</groupId>
            <artifactId>hibernate-jpa-2.1-api</artifactId>
            <version>1.0.0.Final</version>
        </dependency>

        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
        </dependency>

        <dependency>
            <!-- needed for meta model generation (see also compiler plugin config) -->
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-jpamodelgen</artifactId>
            <version>4.3.8.Final</version>
        </dependency>
    </dependencies>
</project>

The AspectJ compiler is configured in the parent project. When I run Maven, the Java compiler plugin is called first and generates the sources to target/generated-sources/generated-sources/annotations correctly. Then the AspectJ plugin is executed which generates the sources again, now into the root folder of my project and throws the following errors:

D:\xxx\git\xxx>mvn clean install
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building xxx 1.0.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ xxx ---
[INFO] Deleting D:\...
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ xxx ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO]
[INFO] --- maven-compiler-plugin:3.2:compile (default-compile) @ xxx ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 63 source files to D:\xxx\git\xxx\target\classes
[INFO]
[INFO] --- aspectj-maven-plugin:1.7:compile (default) @ xxx ---
[INFO] Showing AJC message detail for messages of types: [error, warning, fail]
[WARNING] Hibernate JPA 2 Static-Metamodel Generator 4.3.8.Final
        <unknown source file>:<no line information>

[ERROR] The type Category_ is already defined
        D:\xxx\git\xxx\Category_.java:10
public abstract class Category_ extends com.xxx.AbstractEntity_ {
                      ^^^^^^^^

[ERROR] The type Attachment_Message_ is already defined
         D:\xxx\git\xxx\Attachment_Message_.java:9
public abstract class Attachment_Message_ extends com.xxx.AbstractEntity_ {
                      ^^^^^^^^^^^^^^^^^^

[ERROR] The type AbstractNamedEntity_ is already defined
         D:\xxx\git\xxx\AbstractNamedEntity_.java:9
public abstract class AbstractNamedEntity_ extends com.xxx.AbstractEntity_ {

...

How can I hinder the AspectJ compiler executing the model geneator a second time?

Which AspectJ version do you use? (I am not asking for the aspectj-maven-plugin version, because I can see that this is 1.7) — Ralph, Feb 18 '15 at 18:57

Ralph · Answer 1 · 2015-12-23T09:37:26.913

The point is that is that AspectJ 1.8.2 is the fist version that include the Annotation Processing Feature that causes the generation.

There are two ways to disable the generation:

1) Upgrade you Maven-AspectJ-Plugin Version 1.8, it has a new parameter: proc, set it to none to disable the generation. see GitHub Issue #5,

<plugin>
    <groupId>org.codehaus.mojo</groupId>
    <artifactId>aspectj-maven-plugin</artifactId>
    <version>1.8</version>
    ...
    <configuration>
        ...
       <proc>none</proc>
   </configuration>
</plugin>

or

2) One other "solution" would be to use AspectJ Version 1.8.1, but not 1.8.2+.

score 1 · Answer 2 · answered Jan 19 '15 at 10:18

1

I excluded the model classes from aspectj compiler. This disables Aspects for the model classes (currently not needed) but also the double generation of the meta model classes:

<build>
    <plugins>
        <plugin>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>aspectj-maven-plugin</artifactId>
            <configuration>
                <sources>
                    <source>
                        <basedir>src/main/java</basedir>
                        <excludes>
                            <exclude>**/domain/*</exclude>
                        </excludes>
                    </source>
                </sources>
            </configuration>
            <executions>
                <execution>
                    <goals>
                        <goal>compile</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>

    </plugins>
</build>

answered Jan 19 '15 at 10:18

Jens Baitinger

2,230
14
34

This seems to be a workaround rather than the solution you were looking for. If you are still interested in a solution which would also work if your model classes needed aspect weaving, please update your question and show the actual parent POM. I would like to understand how and where a compiler would generate sources at all (I am not a Hibernate user). Once I do, I might be able to propose a solution. – kriegaex Jan 19 '15 at 14:57
Actually, this is a workaround, excluding the domain classes from weaving (actually there are currently no aspects that regards the model classes). The Hibernate Metamodel generator (http://hibernate.org/orm/tooling/) uses the JPA annotations and generates the meta model classes. It works like a plugin to the compiler. When it is in the dependencies it generates the classes. I never tried to figure out how that works, but it might be interesting to know. – Jens Baitinger Jan 20 '15 at 10:48
Have you seen [this bug report](https://jira.codehaus.org/browse/MASPECTJ-137), describing a problem explained in more detail [here](https://haskovec.com/2014/12/04/maven-compiler-plugins-aspectj-hibernate-metamodel-generator/)? My hints about the AspectJ Maven parameters *Xset* or *argumentFileName* might lead to viable workarounds, but this is just a wild guess. Do you have an [SSCCE](http://sscce.org/) for me to test against? – kriegaex Jan 20 '15 at 13:35
Bug report can now be found here: https://github.com/mojohaus/aspectj-maven-plugin/issues/5 – Dave Aug 25 '15 at 03:40

Maven Aspectj plugin calls the JPA model generator again

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