How to write JSON inside of java

i have a JSON string and i want to write it as a JSON file(.json) inside of java. because my final application needs to import .json file not a string. (i am using spring to create a web app)

this is my json string:

String str = "{"polygons": {"landuse": ["__any__"],"building": ["__any__"],"shop": ["__any__"]}}";

and i want a file (str.json) inside of my java webapp not saving to pc and then importing.

do you have solution for this task?

thanks