Spring for GraphQL: Input-Types containing java.util.Optional with objects fail

Steps to reproduce

• Start Server, open GraphiQL at http://localhost:31080
• Run Query that works:

    mutation {
      createAccount(input:{
        id: "1",
        fullname: "Klaus"
      }
    )}

• Note this query works, even fullname on the Java type AccountInput is a java.util.Optional
• Try to add also a contact:

    mutation {
      createAccount(input:{
        id: "1",
        fullname: "Klaus",
  
        contact:{
          phone: "123"
        }
      })
    }

• This mutation fails (Unable to make private java.util.Optional(java.lang.Object) accessible: module java.base does not "opens java.util" to unnamed module)
• contact on the java record AccountInput is also a java.util.Optional (as fullname is), but contains another Record and not a Java primitive
• Same problem occurs if instead of a Record a regular java class is used (see personalData)