There are several locations in the JDK source where `System.in` and
`FileDescriptor.in` is read with `InputStreamReader` and `Scanner` using the
default charset. As recommended by the recently merged
[JDK-8356420](https://bugs.openjdk.org/browse/JDK-8356420), this PR replaces
the default charset with the one provided by the `stdin.encoding` system
property.
### Fixing strategy
* Where it is obvious that `System.in` is passed to
`InputStreamReader`/`Scanner` ctors, `stdin.encoding` is employed fixed.
* Where the `InputStream` passed to `InputStreamReader`/`Scanner` ctors is
difficult to determine if it can ever be `System.in`, `assert` expressions are
placed.
* Where the odds of receiving `System.in` are low, yet it is technically
possible (e.g., `Process::getInputStream`, `URL::openConnection`,
`Class::getResourceAsStream`), nothing is done.
@naotoj was kind enough to guide me in this PR, and stated `assert` expressions
can be skipped, since they are many ways one can circumvent those checks;
wrapping `System.in`, usage of `System::setIn`, etc. Yet we decided to leave
them as is to collect feedback from other reviewers too.
### Scanning strategy
The following ~alien technology~ advanced static analysis tools are used to
scan the code for potentially affected places:
# Perl is used for multi-line matching
find . -name "*.java" -exec perl -0777 -ne 'my $r =
(/(InputStreamReader|Scanner)(\s*System.in)/) ? 0 : 1; exit $r' {} ; -print
git grep -H 'FileDescriptor.in' "*.java"
All calls to `InputStreamReader::new` and `Scanner::new` are checked too.
### Problems encountered
1. Due to either irregular, or non-existent license header, could not update
the copyright year for following classes:
```
DOMImplementationRegistry
InputRC
ListingErrorHandler
PandocFilter
```
2. Could not employ `stdin.encoding` in `PandocFilter`, since the bootstrap VM
running that class returns empty for that system property
-------------
Commit messages:
- Use `stdin.encoding` in `InputStreamReader` and `Scanner` instantiations
Changes: https://git.openjdk.org/jdk/pull/25368/files
Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25368&range=00
Issue: https://bugs.openjdk.org/browse/JDK-8356893
Stats: 244 lines in 58 files changed: 111 ins; 20 del; 113 mod
Patch: https://git.openjdk.org/jdk/pull/25368.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/25368/head:pull/25368
PR: https://git.openjdk.org/jdk/pull/25368
