Catch block variable warning in Java

Log the exception. It is always useful anyway when chasing a bug.

There's no clean way to "mark ex as used" in Java, except by using it.

Note, however that according to its documentation a FileNotFoundException can also be thrown when "[...] the file does exist but for some reason is inaccessible, for example when an attempt is made to open a read-only file for writing."

Therefore I suggest you do use the exception by also printing message from the exception.

I'm aware that this doesn't answer the general question, but I can hardly think of an exception of which I wouldn't at least log some information when it happens.

Use the @SuppressWarnings("unused") annotation.

See also:

• Annotations tutorial
• Supported Values for @SuppressWarnings