RFR: JDK-8315458 JEP 463: Implementation of Implicitly Declared Classes and Instance Main Method (Second Preview) [v16]

[Jim Laskey]

> Address changes from JEP 445 to JEP 463.
> 
> - Move from a SYNTHETIC unnamed class to a MANDATED implicit class.
> 
> - Don't mark class on read.
> 
> - Remove reflection and annotation processing related to unnamed classes.
> 
> - Simplify main method search.

Jim Laskey has updated the pull request incrementally with five additional commits since the last revision:

 - Simplified and compatible main method finding
 - Update LauncherHelper.java
 - Update tests
 - Misspelling
 - Clean up exception checks

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/16461/files
  - new: https://git.openjdk.org/jdk/pull/16461/files/d3581d89..1bf935f4

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=16461&range=15
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=16461&range=14-15

  Stats: 232 lines in 8 files changed: 99 ins; 102 del; 31 mod
  Patch: https://git.openjdk.org/jdk/pull/16461.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16461/head:pull/16461

PR: https://git.openjdk.org/jdk/pull/16461