HSQLDB - works with external Jar - not with JRE

Question

Using a test app to figure out problems with production application and hsqldb.

If I compile the test app with the hsqldb.jar file as an external jar in eclipse the program works. However, if I only have the jar file in my JRE system library I get a pre-9.0 client attempted to connect error from the database.

The two files are the exact same files. Only difference is one was added as external jar and the other was just in the class path. When production app builds it is using classpath to same file and generating the same pre-9.0 error.

Answer 1

The jar you want to use is an HSQLDB version 2.0 jar. There is a second HSQLDB jar which is version 1.8 and is in your classpath before your intended jar.

This is a classpath issue. You should be able to find where the second jar (1.8) is and how it gets into the classpath by using java -verbose or other debugging options.

[added] An additional step you could take to debug this in your application is to print out the value of the field org.hsqldb.persist.HsqlDatabaseProperties.THIS_FULL_VERSION before connecting to the database. This will print the version of the jar used as the client. A successful connection means the client and server jars are the same version.

The server instance prints out its version to the console when it starts.

I would also recommend using the latest snapshot jar for HSQLDB from the http://hsqldb.org/support/ page.

Answer 2

Sorted out problem by moving hsqldb.jar to first declared in classpath.