driver-legacy/src/main/com/mongodb/gridfs/GridFSDBFile.java
void remove() {
        fs.getFilesCollection().remove(new BasicDBObject("_id", id));
        fs.getChunksCollection().remove(new BasicDBObject("files_id", id));
    }
void remove() {
        fs.getFilesCollection().remove(new BasicDBObject("_id", id));
        fs.getChunksCollection().remove(new BasicDBObject("files_id", id));
    }
Removes file from GridFS i.e. removes documents from files and chunks collections.