use CREATE SCHEMA IF NOT EXISTS NEWSCHEMA
You need to commit one connection before using the other connection.
It may hang when you use an in-process database with a single thread running two transactions simultaneously. If you set up and access a server, the wait pattern will probably be different.
The second data source (connection) is waiting for the first one to commit. No-wait operation is allowed in LOCKS mode in version 2.4.0
Yes. The name in the JDBC URL is used. See the source code for org.hsqldb.DatabaseManager
The actual database instance is kept in static variables. You need to execute SHUTDOWN to close the database and release the memory. So long as you have not executed SHUTDOWN, the database is in memory and can be accessed from any thread in the JVM.
WHEN clause ignored using Java based triggers
Thanks for reporting. Fixed and committed to SVN.