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Bernt Johnsen

Bernt M. Johnsen is technical lead on Apache Derby at Sun's Database Technology Group in Trondheim, Norway. He has 5 years database experience (database management, JDBC drivers, distributed SQL execution). Prior work includes internet banking, compilers and expert systems. He has a wife and 3 boys, and likes to climb (indoor, ice, glaciers, rock) and to kayak in his spare time.


bernt's blog

Java DB 10.2 beta is now available for download. Try it out!

Posted by bernt on August 12, 2006 at 12:47 PM PDT

Java DB (or Derby, or Cloudscape if you prefer) 10.2 beta is available for download at

There has not been a feature release since august 2005, so this should be what Java DB/Derby users are waiting for.

Do you need to learn how to use transactions? Again?

Posted by bernt on June 6, 2006 at 6:34 AM PDT

Statement: A lot of programmers do not know how to use transactions.
You may now think that I miss the target completely, but think for a while.

Very often they (and myself, I admit) think of transactions as atomic
changes to the database and write code like


Open Java DB

Posted by bernt on December 13, 2005 at 12:34 PM PST

Today at ApacheCon in San
Diego, Sun's Tim Bray said that href="">Apache Derby will be distributed
by Sun as the open Java DB.

Java DB (or Derby) will appear in several Sun products and
NetBeans IDE 5.0 will have a Derby (or Java DB) plugin.

So, now we're goi

Apache Derby Released

Posted by bernt on November 24, 2005 at 1:45 AM PST

Apache Derby, the pure Java
SQL database, has released version href="">

The changes since official release include:

  • Globalization of the 10.1 error messages.
  • Eclipse 3.1 support
  • Ability to run on Mac OS X with no special configuration
  • Support for direc

Database benchmarks

Posted by bernt on October 14, 2005 at 2:03 AM PDT

In response to my A Read-only database in a jar? one of the commenters remarked that "Derby is alright but is much slower than HSQL" and referred to a benchmark at

And guess what?

A Read-only database in a jar?

Posted by bernt on October 3, 2005 at 2:26 PM PDT

In Norway, all wines and liquors and beers stronger than 4.75 volume percent are sold at Vinmonopolet a state monopoly (Literally "The Wine Monopoly").

What has this to do with a read only database? Well, I once had an application on my Palm which contained Vinmonopolet's complete catalogue.

Comments on "Easy String Concatenation Considered Harmful?"

Posted by bernt on September 28, 2005 at 2:15 PM PDT

I received some interesting comments on Easy String Concatenation Considered Harmful? and want to comment some of them.

I too love the easy string concatenation of Java.

Easy String Concatenation Considered Harmful?

Posted by bernt on September 20, 2005 at 5:33 AM PDT

This is not about the amount of String objects generated when you do
string concatenation in Java.

JavaZone, Norway

Posted by bernt on September 17, 2005 at 7:09 AM PDT

Since this is my first blog on from a small country, Norway, I'll start with a short comment on Norway & Java.

Norway has a population of around 5 million people, no large cities, lots of beautiful nature, has become rich from vast oil resources and fisheries, and does not bother to be a part of the EU.

Small country?