Google's GSON can do this in a nice way:
Gson gson = new GsonBuilder().setPrettyPrinting().create();
JsonParser jp = new JsonParser();
JsonElement je = jp.parse(uglyJsonString);
String prettyJsonString = gson.toJson(je);
or since it is now recommended to use the static parse method from JsonParser you can also use this instead:
Gson gson = new GsonBuilder().setPrettyPrinting().create();
JsonElement je = JsonParser.parseString?(uglyJsonString);
String prettyJsonString = gson.toJson(je);
Here is the import statement:
import com.google.gson.*;
Here is the Gradle dependency:
implementation 'com.google.code.gson:gson:2.8.7'
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