Well, as you can see for yourself this issue has been logged and accepted as a low priority enhancement. The author(s) of the library may one day decide to implement this. "You are also encouraged to modify and improve the [library] source code directly if you need it right now," as suggested in the reply to the enhancement.
Another way is, if you'll be using the output from
toString() directly, you can manually replace all "\/" character combinations with "/" using
String's
replaceAll method. See
String (Java Platform SE 7 ) . You will need to take care not to over-compensate by testing your code thoroughly.
As for the JSON.simple library itself, you'd find at
https://code.google.com/p/json-simple/downloads/list that the last release was back in Feb 2012. In other words this library is not actively being developed. Usually when using a library you'd want one that has an active community, and has frequent releases for bug fixes and enhancement. Therefore there are grounds for replacing it with another equivalent or similar library. A replacement that I'd recommend is
JSON-java, which is maintained by Douglas Crockford, a leading authority in Javascript, and the person who popularised JSON.