Inconsistent null Handling Across JSONObject Construction Paths #1049

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1. stleary commented on Apr 4, 2026

   

   stleary

   on Apr 4, 2026

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   @venkat-cheenu Thanks for bringing this up. This is a known problem for map parsing. For example, see #296.
   For now, you can use these workarounds:

       @Test
       public void foo() {
           JSONObject jsonObject = new JSONObject();
           Map<String, Object> map = new HashMap<>();
           map.put("mapKeyForNull", null);
           jsonObject = new JSONObject(map, new JSONParserConfiguration().withUseNativeNulls(true));
           jsonObject.put("putKeyForNull", JSONObject.NULL);
           System.out.println(jsonObject.toString(2));
       }
   

   Output:

   {
     "putKeyForNull": null,
     "mapKeyForNull": null
   }
   

   However, it might be reasonable to update the code to accept nulls in maps by default when running in strict mode. Would this work for you?
2. venkat-cheenu commented on Apr 4, 2026

   

   venkat-cheenu

   on Apr 4, 2026

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   Thanks for the detailed comment. @stleary

   The codebase I'm working on uses this library extensively—across about 22,000 files. Is there a way to enable a system-wide configuration to allow NativeNull and overrideDuplicateKey?
3. stleary commented on Apr 4, 2026

   

   stleary

   on Apr 4, 2026

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   @venkat-cheenu Do you have any suggestions on how to do this?
4. venkat-cheenu commented on Apr 5, 2026

   

   venkat-cheenu

   on Apr 5, 2026

   Last edited by venkat-cheenu

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   Hi @stleary,

   To solve this, we could introduce a global, system-wide configuration state while keeping the individual JSONParserConfiguration objects immutable.

   We could add a thread-safe static reference (like an AtomicReference) to hold a default global configuration. It would look something like this for the user:

   Java

   // 1. Define your custom configuration
   JSONParserConfiguration myConfig = new JSONParserConfiguration()
       .withUseNativeNulls(true)
       .withOverwriteDuplicateKey(true);
   
   // 2. Set it globally (do this once during application startup)
   JSONParserConfiguration.setGlobalConfiguration(myConfig);
   

   This approach maintains backward compatibility but gives users a simple "set-and-forget" option so they don't have to pass the config object into every single JSONObject or JSONArray constructor.

   Let me know if you think this is a good direction, and I'd be happy to put together a PR!
5. venkat-cheenu commented on Apr 5, 2026

   

   venkat-cheenu

   on Apr 5, 2026

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   Draft PR : #1050
6. stleary

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   on May 28, 2026