I am not able to connect to my HSQLDB database from RazorSQL. I am only having this issue when I am running in Server mode and when I am attempting to connect from RazorSQL.
Using the same URL from Eclipse Data Source Explorer, and from the application itself (which is a Hibernate 5.2.7 application), I am able to successfully connect to my database at the URL "jdbc:hsqldb:hsql://localhost/SudokuHibernate". Since I am running it in Server mode, I am able to connect concurrently.
(Note: I don't have to have multiple concurrent connections, but it make debugging easier). The database is being run in Server mode from the command line via ...
java -cp ../libs/hsqldb-2.3.4/hsqldb/lib/hsqldb.jar org.hsqldb.server.Server --database.0 file:/Users/arick/src/databases/SudokuHibernate --dbname.0 SudokuHibernate
When attempting to connect from RazorSQL, the database console shows the error message. "org.hsqldb.HsqlException: Client driver version greater than '2.1.0.0' is required. The HSQLDB server version is '2.3.4'".
Note: This is a different question then a similar StackOverflow question, as all of my own configuration files are explicitly referencing the same JDBC driver, from the same jar file. However, as pointed out by Fred T, the reference to '2.1.0.0', by HSQLDB, is somewhat misleading. It is really just saying that the client and the server have two different versions of the JDBC driver.
At the same time that the database is throwing a mismatched version error, RazorSQL displays a dialog box with the error message:
ERROR: An error occurred while trying to make a connection to the database:
JDBC URL: jdbc:hsqldb:hsql://localhost/SudokuHibernate
connection exception: connection failure: java.io.EOFException
Below is my RazorSQL connection profile.
RazorSQL Profile
Driver Location: /Users/arick/src/libs/hsqldb-2.3.4/hsqldb/lib/hsqldb.jar
JDBC URL: jdbc:hsqldb:hsql://localhost/SudokuHibernate
As was inferred by Mark Rotteveel, the answer is similar to a related question about how to get Eclipse and Maven to talk to a HSQLDB server that is running in standalone server mode.
In that case, Fred Toussi, the lead on the HSQLDB project, pointed out the answer was to modify the configuration file, that is used in Eclipse and Maven, to pull in the appropriate version of the HSQLDB JDBC jar file, and also to make sure the jar file didn't appear anywhere else on the classpath. Maven uses a pom.xml file for configuration; so what was needed was make sure that the correct version of the HSQLDB was defined in the project's pom.xml file.
In my situation, the RazorSQL product that I was using, just happens to use HSQLDB as the embedded database for itself. If I had been using any other Java database, I may not have had this problem. But, since the RazorSQL product had already loaded its own version of the HSQLDB jar file, it didn't matter what I specified in my configuration for the database connection. It wasn't going to work.
No matter how I changed my driver profile, or my connection profile, the only version of the HSQLDB jar file that was going to get loaded, was the original jar file, that was already in use by RazorSQL, and that came with RazorSQL. (Note: This is true, unless RazorSQL gets fancy, and it decides to use a different classloader, and some of the other tricks that are commonly used by Java applications servers to solve these problems).
As per suggestion from Dan Richardson, from RazorSQL, the actual answer was not by modifying my configurations, but by changing the contents of the RazorSQL distribution itself. I needed to replace the jar file that is used by the RazorSQL application. This jar file is in Mac application folder for RazorSQL. This location is typically at /Applications/RazorSQL.app/Contents/Java/drivers/hsqldb.
(Note: If you are not familiar with how to open a Mac app folder, you just right-click on the RazorSQL folder name in the /Applications directory and use the "Show Package Contents" menu option). In my case, I renamed the original hsqldb.jar file to be hsqldb_2.3.2.jar file, and then I copied in the last distribution of the hsqldb.jar.