Java works in Unicode and therefore string/character JDBC works with Unicode, however a lot of databases use some specific codepage. I know to my sorrow for example, that you select the codepage when you create a PostgreSQL database, and it's immutable thereafter.
So sometimes you may need a little help in character set translation.
However, Eclipse isn't a
word processor, so there are going to be limits on what it will do. You can select a more appropriate code page for a view display - meaning one that maps the characters in question to appropriate display glyphs. But the underlying data will remain the same.
The secret of how to be miserable is to constantly expect things are going to happen the way that they are "supposed" to happen.
You can have faith, which carries the understanding that you may be disappointed. Then there's being a willfully-blind idiot, which virtually guarantees it.