A summary of why you can't serialize Optional and what can be done to deal with that limitation if necessary.

nipafx (Nicolai Parlog)

Java's Optional class is not serializable and is final, preventing subclassing. Two main scenarios require serializing Optional: as method arguments/return values in RPC frameworks like RMI, and as fields in serializable classes. A SerializableOptional<T> wrapper class is presented that uses the serialization proxy pattern to wrap and unwrap Optional while being serializable. For method signatures, SerializableOptional can be used directly with immediate wrap/unwrap calls. For serializable fields, the serialization proxy can either extract the raw value from the Optional or hold a SerializableOptional instance, with trade-offs in readability versus byte stream size.

Serialize Optional