ObjectDB ObjectDB
Home » Forum » Extending model by "common entity"

Extending model by "common entity"

#1
lwalkowski
lwalkowski's picture
Joined on 2010-08-25

Hi,

I have a question about extending working model with one, common entity, that all other entities will inherit from. For example I have 2 different entities in database with some data: 


@Entity
public class Entity1 implements Serializable {
    private String val1;
    private String val2;

    // (getters and setters here)
}
and the second one: 

@Entity
public class Entity2 implements Serializable {
    private String val4;

    // (getters and setters here)
}
Now I want to create BaseEntity which all common attributes: 

@Entity
public class BaseEntity implements Serializable {
    private String createdBy;
    private Date createdAt;
    private String modifiedBy;
    private Date modifiedAt;   

    // (getters and setters here)
}
Then Entity1 and Entity2 will be modified to inherit from BaseEntity, so: 

@Entity
public class Entity1 extends BaseEntity implements Serializable{}
And the same for Entity2. The problem is, that when I have some data in database, after compiling and running new version of application, I got some errors: 
java.lang.NoClassDefFoundError: pl/hplxtool/model/BaseEntity
  at java.lang.ClassLoader.defineClass1(Native Method) ~[na:1.6.0_22]
  at java.lang.ClassLoader.defineClassCond(ClassLoader.java:632) ~[na:1.6.0_22]
  at java.lang.ClassLoader.defineClass(ClassLoader.java:616) ~[na:1.6.0_22]
  at java.lang.ClassLoader.defineClass(ClassLoader.java:466) ~[na:1.6.0_22]
  at com.objectdb.o.ACL.e(ACL.java:175) ~[objectdb.jar:na]
  at com.objectdb.o.STL.h(STL.java:97) ~[objectdb.jar:na]
  at com.objectdb.o.TYM.findClass(TYM.java:954) ~[objectdb.jar:na]
  at com.objectdb.o.ACL.loadClass(ACL.java:137) ~[objectdb.jar:na]
  at java.lang.ClassLoader.loadClass(ClassLoader.java:248) ~[na:1.6.0_22]
  at com.objectdb.o.TYM.at(TYM.java:931) ~[objectdb.jar:na]
  at com.objectdb.o.UTY.initSysType(UTY.java:317) ~[objectdb.jar:na]
  at com.objectdb.o.TYS.l(TYS.java:163) ~[objectdb.jar:na]
  at com.objectdb.o.TYM.aa(TYM.java:469) ~[objectdb.jar:na]
  at com.objectdb.o.TYM.<init>(TYM.java:229) ~[objectdb.jar:na]
  at com.objectdb.o.MST.aE(MST.java:175) ~[objectdb.jar:na]
  at com.objectdb.o.SHN.U(SHN.java:258) ~[objectdb.jar:na]
  at com.objectdb.o.SHN.I(SHN.java:108) ~[objectdb.jar:na]
  at com.objectdb.o.HND.run(HND.java:119) ~[objectdb.jar:na]
  at java.lang.Thread.run(Thread.java:662) [na:1.6.0_22]

Caused by: java.lang.ClassNotFoundException: pl.hplxtool.model.BaseEntity
  at com.objectdb.o.TYM.findClass(TYM.java:951) ~[objectdb.jar:na]
  at com.objectdb.o.ACL.loadClass(ACL.java:137) ~[objectdb.jar:na] at java.lang.ClassLoader.loadClass(ClassLoader.java:248) ~[na:1.6.0_22]
How can I propagate that kind of changes with ODB model? The same exceptions are thrown when I run explorer or doctor.
✂
edit
delete
#2
support
support's picture
Joined on 2010-05-03

This schema change should be handled by ObjectDB - so the exception is unexpected.

Maybe you have to restart the server (I see that the stack trace is generated by the server).

If it doesn't help - please post (or submit in a support ticket) a test case that demonstrates this exception.

ObjectDB Support
ObjectDB - Fast Object Database for Java (JPA/JDO)
✂
edit
delete
#3
lwalkowski
lwalkowski's picture
Joined on 2010-08-25

Restart didn't help at all. I will prepare test case and submit a support ticket.

✂
edit
delete
#4
support
support's picture
Joined on 2010-05-03

Thank you for the test application - it demonstrates a bug in ObjectDB schema evolution.

Please check build 2.0.5_01 that should fix it.

If possible - apply the schema change again to a database that was used only with the old schema.

If you must repair a database file that was already used with the new schema - open it once in embedded mode from your application (not using the Explorer) - after rebuilding all the classes.

ObjectDB Support
ObjectDB - Fast Object Database for Java (JPA/JDO)
✂
edit
delete

Reply

To post on this website please sign in.

About ObjectDB Getting Started Support
DBMS Features Quick Tour with JPA ObjectDB FAQ
Editions and Prices JPA Console Tutorial ObjectDB Manual
Licence Web App Tutorial Forum
Attributions Java EE JPA Tutorial Issue Tracking
Privacy Spring MVC JPA Tutorial Website Search
Terms of Use Download ObjectDB Contact Us

Which JPA is Faster?

 

See a comparison of Hibernate, EclipseLink, OpenJPA, DataNucleus, MySQL, PostgreSQL, Derby, HSQLDB, DB4O by Versant, H2 Database, SQLite and ObjectDB

in the JPA Benchmark.

Copyright © 2003, 2010, 2023  ObjectDB Software, all rights reserved. The JPA API Reference Documentation (JavaDoc) on this website is derived with some adjustments from the open source JPA 2 RI (EclipseLink) and is available under the terms of the Eclipse Public License, v. 1.0 and Eclipse Distribution License, v. 1.0. The JDO API Reference Documentation (JavaDoc) on this website is derived with some adjustments from the JDO 2.2 API and is available under the terms of the Apache License, v. 2.0. Images on this website are available under these licecnes. Documentation on this website explains how to use JPA in the context of the ObjectDB Object Database but mostly relevant also for ORM JPA implementations, such as Hibernate (and HQL), EclipseLink, TopLink, OpenJPA and DataNucleus. ObjectDB is not an ORM JPA implementation but an Object Database (ODBMS) for Java with built in JPA 2 support.