When you use POST, you can and should specify the charset. If you are doing this, it should work.
Where can I do this? Have you any example? I have a QueryRequest instance, a SolrQuery and a SolrServer instance and set the query by solrQuery.setQuery(query) where "query" is a String containing Japanese characters. Do I have to escape them somehow (Java strings are UTF-16 and not UTF-8 encoded I guess)?
On which instance shall I set the charset and how?