Draft Spec for Flexible Constructor Bodies (JEP 513)

[Remi Forax]

Hello, 
i'm not sure it's wise to have flexible constructor bodies to be out of preview. 

There is a non trivial interaction with the introduction of strict fields and i am not sure those two should be separated, mostly because with strict fields, initializing a field before the call to super() change its semantics while with a flexible constructor body, one can already initialize the field before the call to super() without the semantics being changed. 

But i'm sure i'm missing something ... 

regards, 
Rémi 

> From: "Gavin Bierman" <gavin.bierman at oracle.com>
> To: "amber-spec-experts" <amber-spec-experts at openjdk.org>
> Sent: Tuesday, April 22, 2025 3:48:31 PM
> Subject: Draft Spec for Flexible Constructor Bodies (JEP 513)

> Dear experts,

> The first draft of a spec covering JEP 513 (Flexible Constructor Bodies) is
> available at:

> [ https://cr.openjdk.org/~gbierman/jep513/latest/ |
> https://cr.openjdk.org/~gbierman/jep513/latest/ ]

> Feel free to contact me directly or on this list with any comments/corrections.

> Thanks,
> Gavin

>> On 22 Apr 2025, at 13:02, Mark Reinhold <mark.reinhold at oracle.com> wrote:

>> https://openjdk.org/jeps/513

>> Summary: In the body of a constructor, allow statements to appear
>> before an explicit constructor invocation, i.e., super(...) or
>> this(...). Such statements cannot reference the object under
>> construction, but they can initialize its fields and perform other safe
>> computations. This change allows many constructors to be expressed
>> more naturally. It also allows fields to be initialized before they
>> become visible to other code in the class, such as methods called from
>> a superclass constructor, thereby improving safety.

>> - Mark
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