Read/write: you want to do that programmatically or maybe in a (GUI/other?) editor, which is configured by the XSD? Or validates based on the XSD? Do you actually want to read/write from/to the Oracle database via some method?
XSD: You want to generate these based on data you have as XML, and/or data you get from the Oracle database? Or do you get the XSD from the Oracle database (because it's its table/schema definition)? What about validation rules, do you want to support these too? What about data types, do you want to support these too? Or not? Where did you get the XSD in the attachment from, if you say you have to create XSD(s)? Is it just this one XSD, or many/any?
Oracle database: does the Java code need to interface directly with the database, because that's what you want to read/write from/to? Or keeping these separate/isolated, and you may get/post data from/to the Oracle database by some other method? Do you get the XML from somewhere else, and you want to edit/validate/insert/update it from a separate source into the database?
My price/time is just a placeholder - your project reads as a typical request on first look, but it could be the case that there's many complicating details which are left unclear. For that reason, if yours doesn't turn out to be simple/trivial, I think your price range and maybe even my bid might be too low. But OK, depends.