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  1. JDK
  2. JDK-8237202

Discuss evolution of records in serialization spec

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    Details

    • Type: CSR
    • Status: Closed
    • Priority: P2
    • Resolution: Approved
    • Fix Version/s: 14
    • Component/s: core-libs
    • Labels:
      None
    • Subcomponent:
    • Compatibility Risk:
      minimal
    • Compatibility Risk Description:
      Addendum to the new-in-14 records preview-feature Serialization spec change document.
    • Scope:
      SE

      Description

      Summary

      Describe allowable types of evolution compatible changes to serializable record classes.

      Problem

      The record-specific Java Object Serialization specification is silent on the types of changes that can be made to record classes while maintaining compatibility with preview serial versions.

      Solution

      In subsection 5.6.2 - "Compatible Changes", add allowable types of evolution compatible changes that can be made to serializable record classes.

      Specification

      5.6.2 Compatible Changes

      ...
      -   Adding or removing a record component - When the record object being
          reconstituted has a record component that does not occur in the stream, the
          record class's canonical constructor will be passed the default value for
          its type. If specific initialization is needed, the constructor can
          initialize the component to a non-default value. Stream field values not
          passed to the canonical constructor are effectively discarded.
      
      -   Changing a class from an ordinary class to a record class - A class that is
          suitable to be converted from an ordinary class to a record class, and
          relies on default serialization, may be changed to a record class. The
          ordinary class should have `java.lang.Object` as its direct superclass, or
          otherwise have no serializable state in its superclasses. The name and type
          of the record class's components must match that of the name and type of the
          ordinary class's serializable fields. Record objects are reconstructed
          through the record class's canonical constructor. If the canonical
          constructor throws an exception, say while checking invariants, then an
          `InvalidObjectException` is thrown.
      
      -   Changing a class from a record class to an ordinary class - A record class
          that relies on default serialization, may be changed to an ordinary class.
          The ordinary class must declare an explicit `serialVersionUID`, whose value
          is the same as that of the prior record class's `serialVersionUID`, or
          `0L` if the prior record class does not have an explicit `serialVersionUID`
          declaration. The name and type of the ordinary class's serializable fields
          must match that of the name and type of the prior record class's components.

      Viewable online at: https://cr.openjdk.java.net/~chegar/records/spec/records-serialization-addendum.html

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              Assignee:
              chegar Chris Hegarty
              Reporter:
              darcy Joe Darcy
              Reviewed By:
              Alan Bateman
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                Dates

                Created:
                Updated:
                Resolved: