RFR: 8352693: Use a simpler console reader instead of JLine for System.console() [v2]

[Jan Lahoda]

On Thu, 3 Apr 2025 17:59:52 GMT, Jan Lahoda <jlahoda at openjdk.org> wrote:

>> The `java.io.Console` has several backends: a simple on in `java.base`, a more convenient one in `jdk.internal.le` (with line-reading based on JLine) and one for JShell.
>> 
>> The backend based on JLine is proving to be a somewhat problematic - JLine is very powerful, possibly too powerful and complex for the simple task of editing a line with no completion, no history, no variables, no commands, etc. As a consequence, there are inevitable sharp edges in this backend.
>> 
>> The idea in this PR is to replace the use of JLine in the `jdk.internal.le` backend with a simple escape code interpreter, that only handles a handful of keys/codes (left/right arrow, home, end, delete, backspace, enter), and ignores the rest. The goal is to have something simple with less surprising behavior.
>
> Jan Lahoda has updated the pull request incrementally with three additional commits since the last revision:
> 
>  - Using control characters to get backspace control character.
>  - If there's no native library available, fall back to the standard provider.
>  - Reflecting review feedback.

I have updated the PR based on most of the review comments so far:
- removed the unnecessary qualified exports (https://github.com/openjdk/jdk/pull/24242/commits/91fa1b28e0436e55eed9cdee07e0e28c25bf666a)
- reduced line lengths (https://github.com/openjdk/jdk/pull/24242/commits/91fa1b28e0436e55eed9cdee07e0e28c25bf666a)
- cleaned comments in the C code (https://github.com/openjdk/jdk/pull/24242/commits/91fa1b28e0436e55eed9cdee07e0e28c25bf666a)
- cleaned up the makefiles (https://github.com/openjdk/jdk/pull/24242/commits/91fa1b28e0436e55eed9cdee07e0e28c25bf666a)
- if the native library (for UNIX) is not available, fall back to the simple/default provider (although support for AIX would be great, of course) (https://github.com/openjdk/jdk/pull/24242/commits/c6256eeeabfd73e7e67bf7f8c18c337e6bb92534)
- I realized the backspace value can (and should) be read from the terminal as a control character, so I did that (https://github.com/openjdk/jdk/pull/24242/commits/d5176d68e8cc73914a0efef45a60f0ff03885bcc)

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PR Comment: https://git.openjdk.org/jdk/pull/24242#issuecomment-2776568012