I want to format a string containing JSON data using Java. Does anybody know an open source library for that.
Assuming you're starting out with an existing JSON string, then Jackson can do this for you:
ObjectMapper objectMapper = new ObjectMapper();
objectMapper.configure(SerializationConfig.Feature.INDENT_OUTPUT, true);
String originalJson = ...
JsonNode tree = objectMapper .readTree(originalJson);
String formattedJson = objectMapper.writeValueAsString(tree);