java - How to enhance classes properly at build time using Maven? OpenJPA

Question

I am trying to enhance (entities) classes so i will not get this Exception:

Exception in thread "main" <openjpa-3.1.2-r66d2a72 nonfatal user error> org.apache.op
enjpa.persistence.ArgumentException: Attempt to cast instance "entities.EntityPerson@
6dba847b" to PersistenceCapable failed.  Ensure that it has been enhanced.
FailedObject: entities.EntityPerson@6dba847b
    at org.apache.openjpa.kernel.BrokerImpl.assertPersistenceCapable(BrokerImpl.java:486
3)
    at org.apache.openjpa.kernel.BrokerImpl.persistInternal(BrokerImpl.java:2762)
    at org.apache.openjpa.kernel.BrokerImpl.persist(BrokerImpl.java:2707)
    at org.apache.openjpa.kernel.BrokerImpl.persist(BrokerImpl.java:2690)
    at org.apache.openjpa.kernel.BrokerImpl.persist(BrokerImpl.java:2592)
    at org.apache.openjpa.kernel.DelegatingBroker.persist(DelegatingBroker.java:1197)
    at org.apache.openjpa.persistence.EntityManagerImpl.persist(EntityManagerImpl.java:8
37)
    at openjpa.Test/main.Main.main(Main.java:23)

saying that my instance i am trying to persist is not enhanced.

I have followed this: https://openjpa.apache.org/enhancement-with-maven.html official openjpa page and added openjpa-maven-plugin to the section of my pom.xml:

<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>registry</groupId>
    <artifactId>datalayer</artifactId>
    <version>0.0.1</version>
    <packaging>jar</packaging>

    <properties>
        <maven.compiler.target>11</maven.compiler.target>
        <maven.compiler.source>11</maven.compiler.source>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.sourceEncoding>UTF-8</project.reporting.sourceEncoding>
    </properties>

    <build>
        <pluginManagement>
            <plugins>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.8.1</version>
                </plugin>
                <plugin>
                    <groupId>org.apache.openjpa</groupId>
                    <artifactId>openjpa-maven-plugin</artifactId>
                    <version>3.1.2</version>
                    <configuration>
                        <includes>datalayer/dto/*.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>
            </plugins>
        </pluginManagement>
    </build>

    <dependencies>
        <dependency>
            <groupId>org.apache.openjpa</groupId>
            <artifactId>openjpa</artifactId>
            <version>3.1.2</version>
        </dependency>
        <dependency>
            <groupId>org.apache.derby</groupId>
            <artifactId>derby</artifactId>
            <version>10.15.2.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.derby</groupId>
            <artifactId>derbytools</artifactId>
            <version>10.15.2.0</version>
        </dependency>
    </dependencies>
</project>

, but i still get that exception. I am using Eclipse and built in command Run As -> Maven install. I also tried to run mvn install from command line. Then i just try to persist some entity using EntityManager.

Running mvn install with and without openjpa-maven-plugin does not change anything (same .jar generated with same .class files, same maven output to console)

As answer says, i needed to run openjpa:enhance goal when building with Maven. I was de facto not using openjpa-maven-plugin, so i fixed that. Maven output:

[INFO] Error stacktraces are turned on.
[INFO] Scanning for projects...
[INFO] 
[INFO] -------------------------< registry:datalayer >-------------------------
[INFO] Building datalayer 0.0.1
[INFO] --------------------------------[ jar ]---------------------------------
[INFO] 
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ datalayer ---
[INFO] Deleting C:\Users\wortigson\Desktop\ISMatrikaBcWorkspace\Openjpa.Test\target
[INFO] 
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ datalayer ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 1 resource
[INFO] 
[INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) @ datalayer ---
[WARNING] Can't extract module name from geronimo-jms_1.1_spec-1.1.1.jar: geronimo.jm
s.1.1.spec: Invalid module name: '1' is not a Java identifier
[WARNING] Can't extract module name from geronimo-jta_1.1_spec-1.1.1.jar: geronimo.jt
a.1.1.spec: Invalid module name: '1' is not a Java identifier
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 3 source files to C:\Users\wortigson\Desktop\ISMatrikaBcWorkspace\Op
enjpa.Test\target\classes
[INFO] 
[INFO] --- openjpa-maven-plugin:3.1.2:enhance (default-cli) @ datalayer ---
130  DataLayer  INFO   [main] openjpa.Tool - Enhancer running on type "class entities
.EntityPerson".
[INFO] 
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ datalayer ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 1 resource
[INFO] 
[INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) @ datalayer ---
[WARNING] Can't extract module name from geronimo-jms_1.1_spec-1.1.1.jar: geronimo.jm
s.1.1.spec: Invalid module name: '1' is not a Java identifier
[WARNING] Can't extract module name from geronimo-jta_1.1_spec-1.1.1.jar: geronimo.jt
a.1.1.spec: Invalid module name: '1' is not a Java identifier
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 3 source files to C:\Users\wortigson\Desktop\ISMatrikaBcWorkspace\Op
enjpa.Test\target\classes
[INFO] 
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ datalay
er ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 0 resource
[INFO] 
[INFO] --- maven-compiler-plugin:3.8.1:testCompile (default-testCompile) @ datalayer 
---
[WARNING] Can't extract module name from geronimo-jta_1.1_spec-1.1.1.jar: geronimo.jt
a.1.1.spec: Invalid module name: '1' is not a Java identifier
[WARNING] Can't extract module name from geronimo-jms_1.1_spec-1.1.1.jar: geronimo.jm
s.1.1.spec: Invalid module name: '1' is not a Java identifier
[INFO] Changes detected - recompiling the module!
[INFO] 
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ datalayer ---
[INFO] 
[INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ datalayer ---
[INFO] Building jar: C:\Users\wortigson\Desktop\ISMatrikaBcWorkspace\Openjpa.Test\tar
get\datalayer-0.0.1.jar
[INFO] 
[INFO] --- maven-install-plugin:2.4:install (default-install) @ datalayer ---
[INFO] Installing C:\Users\wortigson\Desktop\ISMatrikaBcWorkspace\Openjpa.Test\target
\datalayer-0.0.1.jar to C:\Users\wortigson\.m2\repository\registry\datalayer\0.0.1\da
talayer-0.0.1.jar
[INFO] Installing C:\Users\wortigson\Desktop\ISMatrikaBcWorkspace\Openjpa.Test\pom.xm
l to C:\Users\wortigson\.m2\repository\registry\datalayer\0.0.1\datalayer-0.0.1.pom
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS

You can see i run enhancer on EntityPerson class, which is simple JPA entity i tested this on. However i still get that Exception. I noticed maven-compiler-plugin:3.8.1:compile running twice. Before and after openjpa-maven-plugin:3.1.2:enhance - might this be problem?

I think this is not my case: How to enhance a class from a separate jar at build time with openJPA?

Found there is workaround Attempt to cast instance to PersistenceCapable failed. Ensure that it's been enhanced by setting some attribute in configuration as accepted answer says, but i do not want to do it that way, as first comment says it is not recommended and points to the official openjpa page, where i found that example how to enhance classes during maven build time, but as i wrote, it does not work.

Testing main method:

public static void main(String[] args)
    {
        HashMap<String, String> jpaProps = new HashMap<String, String>();
        jpaProps.put("javax.persistence.jdbc.url", "jdbc:derby:testDB;create=true");
        EntityManagerFactory factory = Persistence.createEntityManagerFactory("DataLayer", jpaProps);
        EntityManager manager = factory.createEntityManager();
        EntityPerson person = new EntityPerson();
        person.setAge(25);
        person.setName("Andrej Hruska");
        manager.persist(person); // +
    }

EntityPerson class:

package entities;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;

@Entity
public class EntityPerson
{
    @Id
    @GeneratedValue
    private long id;
    
    @Column(nullable = false)
    private String name;
    
    private int age;

    public long getId()
    {
        return id;
    }

    public void setId(long id)
    {
        this.id = id;
    }

    public String getName()
    {
        return name;
    }

    public void setName(String name)
    {
        this.name = name;
    }

    public int getAge()
    {
        return age;
    }

    public void setAge(int age)
    {
        this.age = age;
    }
}

persistence.xml:

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.2"
    xmlns="http://xmlns.jcp.org/xml/ns/persistence"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence https://www.oracle.com/webfolder/technetwork/jsc/xml/ns/persistence/persistence_2_2.xsd">
    <persistence-unit name="DataLayer"
        transaction-type="RESOURCE_LOCAL">
        <non-jta-data-source>DataSource</non-jta-data-source>
        <properties>
            <property
                name="javax.persistence.schema-generation.database.action"
                value="create" />
            <property name="javax.persistence.jdbc.driver"
                value="org.apache.derby.jdbc.EmbeddedDriver" />
            <property name="javax.persistence.jdbc.url"
                value="jdbc:derby:db;create=true" />
        </properties>
    </persistence-unit>
</persistence>

Project structure:

Steps to reproduce:

Crete Maven project in Eclipse
Copy my pom.xml (or add dependencies to derby, openjpa and set up your openjpa-maven-plugin, names and paths)
Copy my persistence.xml (or create your own with some persistence unit)
Copy my EntityPerson class (or create simple JPA entity to test it on)
Run mvn clean compile openjpa:enhance install (important part is openjpa:enhance)
Try to persist entity as i did in my main method

score 3 · Accepted Answer

Move the plugin definition to from <pluginManagement> to <plugins> like

<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>registry</groupId>
    <artifactId>datalayer</artifactId>
    <version>0.0.1</version>
    <packaging>jar</packaging>

    <properties>
        <maven.compiler.target>11</maven.compiler.target>
        <maven.compiler.source>11</maven.compiler.source>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.sourceEncoding>UTF-8</project.reporting.sourceEncoding>
    </properties>

    <build>
        <pluginManagement>
            <plugins>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.8.1</version>
                </plugin>
            </plugins>
        </pluginManagement>
        <plugins>
                <plugin>
                    <groupId>org.apache.openjpa</groupId>
                    <artifactId>openjpa-maven-plugin</artifactId>
                    <version>3.1.2</version>
                    <configuration>
                        <includes>datalayer/dto/*.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>
       </plugins>
    </build>

    <dependencies>
        <dependency>
            <groupId>org.apache.openjpa</groupId>
            <artifactId>openjpa</artifactId>
            <version>3.1.2</version>
        </dependency>
        <dependency>
            <groupId>org.apache.derby</groupId>
            <artifactId>derby</artifactId>
            <version>10.15.2.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.derby</groupId>
            <artifactId>derbytools</artifactId>
            <version>10.15.2.0</version>
        </dependency>
    </dependencies>
</project>

PluginManagement is only for configuration -- the plugins are not run automatically.

score 2 · Accepted Answer

You need to tell maven to run the enhance goal.

mvn clean compile openjpa:enhance

You should see this output:

[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ jpa-example ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 2 source files to /home/gordon/docs/programming/openjpa/jpa-example/target/classes
[INFO] 
[INFO] --- openjpa-maven-plugin:3.1.2:enhance (default-cli) @ jpa-example ---
[INFO]

There is a hierarchy in maven. At the top are lifecycles which are composed of phases that are are implemented as plugin goals. The packaging determines the goals for a phase.

The enhance goal is not one of the default goals for build or compile.

In eclipse, if you change the pom.xml you need to right click and select Maven->Update Project. You can put your openjpa:enhance in the goals field on the eclipse run configurations for Maven Build.

score 1 · Accepted Answer

A few misundestandings.

I have tried using only openjpa-maven-plugin without maven-compiler-plugin, but it did not help.

Maven's pom.xml is considered a "project object model" That means, for your "project" it is the "object" that "models" the build process. This object is sub-classed from a "parent pom.xml" that is embedded inside of Maven, which defines a default build; so, if you remove the "maven-compiler-plugin" you will get the default "maven-compiler-plugin" configuration. Odds are that configuration is quite old, being shipped with Maven, and you probably are better off including an "override" which brings it up to date.

Eclipse and Maven

Eclpise and Maven work together; but, until you know how they work together, you will have a lot of problems.

Eclipse reads the pom.xml file and generates a Eclipse configuration that should perform the same steps as the pom.xml file, in the same ways. When you compile with Eclipse, it doesn't run mvn compile, it builds off of the Eclipse configuration, which might be older than the recently edited pom.xml. For this reason, you should reread your project configuration after every edit of pom.xml when using ecplise.

If you want to look at a different IDE that is similar to Eclipse; but, one that calls mvn compile instead of calling it's own interperted version of "should be the same, but often isn't", look at NetBeans. https://netbeans.apache.org/download/nb122/index.html Unlike Ecplipse, it doesn't contain its own "mirror image of commands" for Maven plugins (or its own embedded compiler), it uses the mvn command and the javac compiler and launches them with configurations to generate a lot of output messages, which it then reads to update it's "IDE side" of things.

The reason I point this out, is because you might be following the instructions, and if you are, you might be seeing correct output on a mvn package from the command line, but not within Eclipse (because of the need to refresh the eclipse project from the source pom.xml)

java - How to enhance classes properly at build time using Maven? OpenJPA

3 回答 3

Eclipse and Maven

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