Derby: Unable to connect. Cannot establish connection to <derby databas url>

[theunsheydenrych]

I would appreciate it if somebody can give me explanation of what
happend with my derby database.

The database was operational for sometime without any troubles, and was
behaving. Today i removed a record from a table by using the "Delete
Selected Record(s)" button from the SQL Command page in Netbeans.
I may had finger trouble and used the "Truncate Table" button.

But all of a sudden the table disappeared from the list, i decided then
to close everything and try to connect again, where i get the following
message:

"Unable to connect. Cannot establish a connection to <derbydb url> using
org.apache.derby.jdbc.Clientdriver(DERBY SQL Error: SQLCODE: -1,
SQLSTATE XJ040, XSQLERRMC: Failed to start database <derbydb url>. see
the next exception for more details"

While playing around trying to get the database back online again, i
noticed that when setting up a jdbc:derby network connection, that when
the wizard ask to select a schema from the database, it by default
choose the "APP" schema and my schema is not available in the list.

I then renamed the database folder, of the database, set a new
jdbc:derby connection up to the database and all of a sudden my schema
is available, and everything is back to normal again.

What happened?
1. After a truncate of a table, the schema is gone?
2. After renaming the database folder, the schema is back?

Regards
Theuns Heydenrych