Is it possible to search for unanswered questions AND no other language than language L, for example, only unanswered Java questions? I would like to list all unanswered questions for a given tag.
Yes you can search by unanswered and by tag:
[java] is:question answers:0
The square brackets denote the tag, and the search tips of
is:question makes sure it's a question, the
answers:0 search tip makes sure there are 0 answers.
The search results page has a link in the side bar that expands like this:
The link at the bottom points to this help center page