jdbc does not work on with blackdown jdk1.2-prev2

I have a redhat6.0 system (kernel upgraded to 2.2.13) with blackdown jdk
1.2pre-v2 installed. I installed postgresql 6.5.3 from the rpms and put
/usr/lib/pgsql/jdbc6.5-1.2.jar in my classpath.

When using the example program from
http://www.oreilly.com/catalog/jenut/examples/ExecuteSQL.java I get:

[jks(at)d1 ~/examples] java -Djdbc.drivers=postgresql.Driver ExecuteSQL
jdbc:postgresql:///template1
Something unusual has occured to cause the driver to fail. Please report
this exception: java.lang.NullPointerException
SQL State: null
Usage: java ExecuteSQL [-d <driver>] [-u <user>] [-p <password>]
<database URL>
[jks(at)d1 ~/examples] java -version
java version "1.2"
Classic VM (build Linux_JDK_1.2_pre-release-v2, green threads, sunwjit)

... when I have /usr/lib/pgsql/jdbc6.5-1.1.jar in my classpath I get
[jks(at)d1 ~/examples] java -Djdbc.drivers=postgresql.Driver ExecuteSQL
jdbc:postgresql:///template1
The postgresql.jar file does not contain the correct JDBC classes for
this JVM. Try rebuilding. If that fails, try forcing the version
supplying it to the command line using the argument -Djava.version=1.1
or -Djava.version=1.2
Exception thrown was java.lang.ClassNotFoundException:
postgresql.jdbc2.Connection
SQL State: null
Usage: java ExecuteSQL [-d <driver>] [-u <user>] [-p <password>]
<database URL>

... from the web mailing list archives I found some other people had
similar problems, but the archive search tool is not very good and I
have not seen any replies with solutions or follow-ups indicating that
this is a known bug.