How to convert ManagedCursorStreamProvider to JSOn object in mule 4
Mule doesn't know how to convert to a GSON JsonObject. You can use DataWeave to transform it into a Java map. Alternatively, you can change the argument of the Java method to String and Mule will transparently convert the stream to a String. Be sure to use the latest version of the Java module.
If you want to convert to a custom type of object you will need to implement it yourself in Java.