Fix the Java generator to generate valid @RequestMappings where the produce field takes list of string parameters instead of a single comma-separated string

[larsenf-els]

Fix AbstractJavaCodegen.getAccepts() so it returns a String[] instead of a comma-separated string, and fixed api.mustache so the @RequestMapping annotation generates the produce field for x-accepts to take a list of string parameters (valid) instead of a single comma-separated string (invalid).

Before this change, the spring generator generated this invalid @RequestMapping:

    @RequestMapping(
        method = RequestMethod.PUT,
        value = "/customers",
        produces = "application/json,application/problem+json", // invalid!
        consumes = "application/json"
    )

The issue here is that the @RequestMapping annotation does not accept a comma-separated list with the produces parameter.
It needs to be generated as a list of strings like this:

    @RequestMapping(
        method = RequestMethod.PUT,
        value = "/customers",
        produces = { "application/json", "application/problem+json" }, // valid
        consumes = "application/json"
    )

@bbdouglas (2017/07) @sreeshas (2017/08) @jfiala (2017/08) @lukoyanov (2017/09) @cbornet (2017/09) @jeff9finger (2018/01) @karismann (2019/03) @Zomzog (2019/04) @lwlee2608 (2019/10) @martin-mfg (2023/08)

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to fix #18058

[MelleD]

Why do you need this import? I guess you have organize the imports again

[larsenf-els]

Why do you need this import? I guess you have organize the imports again

Yes, I saw that IntelliJ had reorganized the imports and that the import you mentioned could be removed as well. :)

[MelleD]

Why not directly producesInfo.toArray?

[larsenf-els]

I did it to guarantee the sort order as I saw the output for the produces field was output in another order when generating all the scripts. But it seems like this is not the case (anymore). So I have updated the code to follow your suggestion. :)

[MelleD]

Looks good, thanks :)

[wing328]

can you please resolve the merge conflicts when you've time? then i will merge

thanks for the PR

[larsenf-els]

can you please resolve the merge conflicts when you've time? then i will merge

thanks for the PR

You are welcome. I am glad that I can give contribute back to the community when I am a big fan of the OpenAPI generator. 😄

I have fixed the merge conflict, and also made a minor bugfix that caused some checks to fail. We should be good to go now.

[wing328]

Thanks for contributing back 👍