MongoCursor<Document> cursor = ((MongoCollection)data).find().iterator();

try {
 response.getWriter().write("[");
 while (cursor.hasNext()) {
 response.getWriter().write(cursor.next().toJson() + (cursor.hasNext() ? "," : ""));
 }
 response.getWriter().write("]");
} finally {
 cursor.close();
}

// applying some json techniques

MongoCursor<Document> cursor = ((MongoCollection)data).find().iterator();
JsonWriter jsonWriter = new JsonWriter(response.getWriter());
jsonWriter.writeStartDocument();
jsonWriter.writeStartArray();

while(cursor.hasNext()) {
    jsonWriter.writeStartDocument();
    jsonWriter.writeString(cursor.next().toJson());
    jsonWriter.writeEndDocument();
}

jsonWriter.writeEndArray();
jsonWriter.writeEndDocument();

cursor.close();