json « HashMap « Java Collection Q&A

1. Java HashMap vs JSONObject    stackoverflow.com

I am wondering about the performance of Java HashMap vs JSONObject. It seems JSONObject stores data internally using HashMap. But JSONObject might have additional overhead compared to HashMap. Does any one know ...

2. Java and json jackson problem    stackoverflow.com

i have this little code, and i'm trying to convert a json string to a map.

String json = "[{'code':':)','img':'<img src=/faccine/sorriso.gif>'}]";
ObjectMapper mapper = new ObjectMapper();
Map<String,String> userData = mapper.readValue(json,new TypeReference<HashMap<String,String>>() { });

3. Returning hashmap objects instead of explicitly defined dto instances (bad practice?)    stackoverflow.com

I found out that since JSON doesn't make a difference between hashes and objects, I can bypass the "law" of always sticking to dto classes, and instead return an "on-the-fly" hashmap, ...

4. Java XStream with HashMap    stackoverflow.com

I want to use XStream to convert a java hash to a json hash. I feel like this should be easier than it seems. What I'm looking for is ...

5. hashmap to json    java-forums.org

JSONObject is complaining that the keys in the map you supplied are not of type String. It requires the keys to be strings. Of what class are the keys in mp? If you're not sure, add after the third line: Class clazz = mp.keySet().iterator().next().getClass(); // assert !mp.isEmpty() System.out.println(clazz); // hopefully you have access to stdout from tomcat. otherwise, print to the ...