David R. Heffelfinger

1. How can I have a composite primary key in JPA?
   
   There are several ways to do it, this page explains them.
   
   
2. How can I prevent users from overwriting each other's changes to the database?
   
   Use the @Version annotation.
   
   
3. Is there a way to do bulk updates and/or deletes with the Java Persistence Query Language (JPQL)?
   
   Yes.
   
   

Since I just upgraded JavaDB, I figured this was a good time to upgrade to the latest version of roller as well. I was using roller 4.0, which is fairly up to date, but I figured it wouldn't hurt to upgrade to the latest, 4.0.1.

I simply downloaded roller 4.0.1, created a war file from the roller directory and deployed it to GlassFish, but for some reason the upgrade didn't go smoothly, I kept getting a "Roller Weblogger has not been bootstrapped yet" error.

I tried various ways of deploying, using asadmin, copying the war file to the autodeploy folder, etc, but I kept getting the same error. I restarted GlassFish several times, I restarted the database (JavaDB/Derby) several times, nothing seemed to solve the problem.

I then decided to reinstall roller 4.0 (thank goodness I made a backup), and it came back up successfully. After doing this, I then redeployed roller 4.0.1 using a different temporary context root, and this time, it installed successfully, asking me to upgrade the database. I did upgrade the database (the only thing that needs to be done when going from roller 4.0 to roller 4.0.1 is change the version number), and I had both roller 4.0 and 4.01 running in parallel with different context roots.

I then undeployed roller 4.0, and changed the context root of 4.0.1 to match the one I had in 4.0 (/roller), I am now in business.

Why wouldn't roller 4.0.1 just install over 4.0 is anyone's guess, however I was glad I was able to work around the issue.

Like I mentioned in My very first entry in this blog, I am running Apache Roller to run this blog.

I'm using GlassFish and Java DB, which isn't much more than a rebranded version of Apache Derby.

The setup was working OK, but every now and then Roller would throw some weird errors, valid URLs would 404, and sometimes it would go completely "out to lunch", generating error 500's.

I started looking through the GlassFish logs and noticed some entries similar to the following:


Caused by: java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
at java.util.ArrayList.RangeCheck(ArrayList.java:547)
at java.util.ArrayList.get(ArrayList.java:322)
at org.apache.derby.client.net.NetCursor.findExtdtaData(Unknown Source)
at org.apache.derby.client.net.NetCursor.getClobColumn_(Unknown Source)
at org.apache.derby.client.am.Cursor.getString(Unknown Source)

I googled around and found out this issue is caused by a bug on JavaDB/Derby version 10.3.2.1 and earlier. I happened to be running 10.3.2.1. I just upgraded to version 10.3.3.0 of JavaDB/Derby. I expect the weird errors I've been seeing to go away now.