No registered metadata for type - Java EE

Не могу понять в чём проблема. OpenJpa выдаёт такую ошибку:

Caused by: java.lang.IllegalStateException: No registered metadata for type "class org.apache.fineract.portfolio.myfirstmodule.domain.MyFirstModule". 
This can happen if this class has not been annotated as a persistent entity or specified in the persistence unit (ex: in the orm.xml).
at org.apache.openjpa.enhance.PCRegistry.getMeta(PCRegistry.java:252) ~[openjpa-all-2.4.1.jar:2.4.1]
at org.apache.openjpa.enhance.PCRegistry.newInstance(PCRegistry.java:110) ~[openjpa-all-2.4.1.jar:2.4.1]
at org.apache.openjpa.meta.ClassMetaData.resolveMeta(ClassMetaData.java:1927) ~[openjpa-all-2.4.1.jar:2.4.1]
at org.apache.openjpa.meta.ClassMetaData.resolve(ClassMetaData.java:1808) ~[openjpa-all-2.4.1.jar:2.4.1]
at org.apache.openjpa.meta.MetaDataRepository.processBuffer(MetaDataRepository.java:829) ~[openjpa-all-2.4.1.jar:2.4.1]
at org.apache.openjpa.meta.MetaDataRepository.resolveMeta(MetaDataRepository.java:726) ~[openjpa-all-2.4.1.jar:2.4.1]
at org.apache.openjpa.meta.MetaDataRepository.resolve(MetaDataRepository.java:650) ~[openjpa-all-2.4.1.jar:2.4.1]

Вот domain файл MyFirstModule.java:

package org.apache.fineract.portfolio.myfirstmodule.domain;
import org.apache.fineract.infrastructure.core.domain.AbstractPersistableCustom;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Table;
import java.sql.Timestamp;
@Entity
@Table(name = "my_first_module")
public class MyFirstModule extends AbstractPersistableCustom<Long> {
@Column(name = "my_test")
private String myTest;
@Column(name = "created_at")
private Timestamp createdAt;
public String getMyTest() {
    return this.myTest;
}
public void setMyTest(String myTest) {
    this.myTest = myTest;
}
public Timestamp getCreatedAt() {
    return createdAt;
}
public void setCreatedAt(Timestamp createdAt) {
    this.createdAt = createdAt;
}
public MyFirstModule(final String myTest, Timestamp createdAt) {
    this.myTest = myTest;
    this.createdAt = createdAt;
}
public MyFirstModule() {
}

public MyFirstModule(final String myTest) {
    this.myTest = myTest;
}

}

Абстрактный класс AbstractPersistableCustom.java:

package org.apache.fineract.infrastructure.core.domain;
import java.io.Serializable;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.MappedSuperclass;
import org.springframework.data.domain.Persistable;

@MappedSuperclass
public abstract class AbstractPersistableCustom<PK extends Serializable> implements Persistable<Long> {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    /*
     * (non-Javadoc)
     * 
     * @see org.springframework.data.domain.Persistable#getId()
     */
    @Override
    public Long getId() {
            return id;
    }
    /**
     * Sets the id of the entity.
     * 
     * @param id the id to set
     */
    protected void setId(final Long id) {
            this.id = id;
    }
    /*
     * (non-Javadoc)
     * 
     * @see org.springframework.data.domain.Persistable#isNew()
     */
    @Override
    public boolean isNew() {
            return null == this.id;
    }
    //We have removed toString(), hashCode() and equals() methods. By adding them end up issues with OpenJPA
}

База:

CREATE TABLE `my_first_module` (
`id` BIGINT(20) NOT NULL AUTO_INCREMENT,
`my_test` VARCHAR(50) NULL DEFAULT NULL,
`created_at` DATETIME NULL DEFAULT NULL,
PRIMARY KEY (`id`)
)
COLLATE='utf8_general_ci'
ENGINE=InnoDB

Как по мне, всё это должно было работать, но в чём дело не могу понять.