DBObject idMatch = new BasicDBObject("user_id","bc");
DBObject usernameMatch = new BasicDBObject("user_name",bc);
DBObject ageMatch = new BasicDBObject("age",2);
DBObject andAll = new BasicDBObject("$and", Arrays.asList(existence, firstNotMatch, secondNotMatch));
//calling table.find will get you what you wanted.
table.find(andAll);
If you want to 'OR' the conditions, just replace $and with $or.
note that the above code is not tested properly and you may need to modify it a bit to make it work.
Your question is not clear, but i hope i helped.
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