How can I solve ORA-00911: invalid character error?

Remove the semicolon (;), backtick (``) etc. from inside a query

If a special character other than $, _, and # is used in the name of a column or table, the name must be enclosed in double quotations. Link

The statement you're executing is valid. The error seems to mean that Toad is including the trailing semicolon as part of the command, which does cause an ORA-00911 when it's included as part of a statement - since it is a statement separator in the client, not part of the statement itself.

It may be the following commented-out line that is confusing Toad (as described here); or it might be because you're trying to run everything as a single statement, in which case you can try to use the run script command (F9) instead of run statement (F5).

Just removing the commented-out line makes the problem go away, but if you also saw this with an actual commit then it's likely to be that you're using the wrong method to run the statements.

There is a bit more information about how Toad parses the semicolons in a comment on this related question, but I'm not familiar enough with Toad to go into more detail.

Remove the semicolon ( ; ).

In oracle, you can use semicolon or not when u ran query directly on DB. But when u using java to ran a oracle query, u have to remove semicolon at the end.