Blessed modifier order does not include sealed/non-sealed

[Pavel Rappo]

While we are here, I also note that the script does not explicitly take into account the `default` modifier on an interface method. However, after reading https://docs.oracle.com/javase/specs/jls/se21/html/jls-9.html#jls-9.4 it seems that whenever `default` appears, it should be alone one way or another; thus, ordering is not an issue.

Indeed, here are the modifier possibilities for an interface method declaration:

    public private abstract default static strictfp

And here are the relevant constraints:

  - explicit public is discouraged
  - abstract, default, and static are mutually exclusive
  - strictfp is obsolete
  - private and default are mutually exclusive

So if `default` appears, except for uncompilable, discouraged, or obsolete cases, it should be alone. Thoughts?

> On 2 Jan 2024, at 17:23, Roger Riggs <roger.riggs at oracle.com> wrote:
> 
> Hi Pavel,
> 
> I agree, the script should refer to the JLS.
> Some people look to the javadoc but its not authoritative on the language.
> 
> Roger
> 
> On 1/2/24 12:18 PM, Pavel Rappo wrote:
>> Right, the language model (javax.lang.model) is a better target to refer to when considering _source_ files. However, java.lang.reflect.Modifier corresponds to a set returned by javax.lang.model.element.Element#getModifiers, not to a single instance of javax.lang.model.element.Modifier; the order of that set is unspecified.
>> 
>> So perhaps the right thing would be to directly refer to JLS from the script. What do you think?
>> 
>>> On 2 Jan 2024, at 16:56, Roger Riggs <roger.riggs at oracle.com> wrote:
>>> 
>>> Hi Pavel,
>>> 
>>> It better to look to javax.lang.model.element.Modifier for the language view of the class.
>>> 
>>> java.lang.reflect.Modifier covers the modifier flags as represented in the class file and defined in the JVMS.
>>> * The values for the constants
>>> * representing the modifiers are taken from the tables in sections
>>> * {@jvms 4.1}, {@jvms 4.4}, {@jvms 4.5}, and {@jvms 4.7} of
>>> * <cite>The Java Virtual Machine Specification</cite>.
>>> Sealing is represented in the class file as a non-empty list of permitted classes. Hence the method of java.lang.Class.
>>> 
>>> Since java.lang.Modifier.toString is based on the flag bits from the class file, "sealed" would not appear in any string it generates.
>>> 
>>> 
>>> It might be possible to inject a comment in the toString method similar to the comment about interface not being a true modifier and including a reference to the javax.lang.model.element.Modifier enum.
>>> 
>>> Roger
>>> 
>>> 
>>> On 1/2/24 11:31 AM, Pavel Rappo wrote:
>>>> Hi Roger,
>>>> 
>>>> Happy New Year to you too!
>>>> 
>>>> Although it's a _somewhat_ separate issue, I found that the shell script refers to java.lang.reflect.Modifier#toString which does NOT mention either `sealed` or `non-sealed`. More precisely, the script refers to the JDK 8 version of that method, but [the method](https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/lang/reflect/Modifier.html#toString(int)) hasn't changed since 2009 and states that:
>>>> 
>>>> ...The modifier names are returned in an order consistent with the suggested modifier orderings given in sections 8.1.1, 8.3.1, 8.4.3, 8.8.3, and 9.1.1 of The Java Language Specification. The full modifier ordering used by this method is:
>>>> 
>>>> public protected private abstract static final transient volatile synchronized native strictfp interface
>>>> 
>>>> It does not seem like `sealed` and `non-sealed` are even modelled by java.lang.reflect.Modifier, although `sealed` is modelled by `java.lang.Class#isSealed`. It cannot be overlook, can it?
>>>> 
>>>> 
>>>>> On 2 Jan 2024, at 14:38, Roger Riggs <roger.riggs at oracle.com> wrote:
>>>>> 
>>>>> Hi Pavel,
>>>>> 
>>>>> yes, a PR would be next.
>>>>> 
>>>>> Happy New Year, Roger
>>>>> 
>>>>> On 1/2/24 7:08 AM, Pavel Rappo wrote:
>>>>> 
>>>>>> I assume the order for `sealed` and `non-sealed` has effectively been decided by JLS: https://docs.oracle.com/javase/specs/jls/se21/html/jls-8.html#jls-8.1.1
>>>>>> 
>>>>>> 8.1.1. Class Modifiers
>>>>>> ...
>>>>>> ClassModifier:
>>>>>> (one of)
>>>>>> Annotation public protected private
>>>>>> abstract static final sealed non-sealed strictfp
>>>>>> ...
>>>>>> 
>>>>>> If two or more (distinct) class modifiers appear in a class declaration, then it is customary, though not required, that they appear in the order consistent with that shown above in the production for ClassModifier.
>>>>>> 
>>>>>> 
>>>>>> Shall I just create a PR?
>>>>>> 
>>>>>> 
>>>>>>> On 2 Jan 2024, at 11:56, Pavel Rappo <pavel.rappo at oracle.com> wrote:
>>>>>>> 
>>>>>>> I couldn't find any prior discussions on this matter.
>>>>>>> 
>>>>>>> I noticed that bin/blessed-modifier-order.sh has not been updated for the [recently introduced](https://openjdk.org/jeps/409) `sealed` and `non-sealed` keywords. I also note that we already have cases in OpenJDK where those keywords are ordered differently. If we have a consensus on how to extend the "blessed order" onto those new keywords, I can create a PR to update the script.
>>>>>>> 
>>>>>>> -Pavel
>>>>>>> 
>>>>>>> 
>