> But the following coding does not help:
>
> Properties properties = new Properties ();
> properties.put("user", "sysdba");
> properties.put("password", "masterkey");
> properties.put("lc_ctype", "ISO8859_1");
>
> The exception I get is still the same.
>
> I set this properties before writing and reading.
>
> Is this correct for Germany?
>
> Do I need any changes to the database?

lc_ctype should be the same as in your database/columns. If you have
different charset specified for different columns, you might get this
exception when there's no translation possible from your client
connection encoding to one of your column encodings.

If you didn't specify anything in the database (neither default
encoding for a database, nor encoding for a column), this means that
you have NONE implicitly defined by server. There's one issue with
NONE: if your connection has non-NONE encoding specified you have
only one way direction for data (you can write but cannot read). So,
the only solution is to specify NONE for your connection explicitly
(lc_ctype=NONE). If you have multiple encodings in database you
should try lc_ctype=UNICODE_FSS.

For Germany you can use WIN1252, works for me fine. But note, you
need to specify encoding for your database/columns. WIN1252 will
provide you correct collation order for umlauts, NONE will not. Or
you can use UNICODE_FSS everywhere, which seems to be Java way of
doing things. :)

Best regards,
Roman Rokytskyy