RFR: 8177418: NPE is not apparent for methods in java.util.TimeZone API docs [v5]

[Justin Lu]

> When their input is null, the following methods in java.util.TimeZone throw a NullPointerException:
> 
> TimeZone.getTimeZone(String ID)
> TimeZone.setID(String ID)
> TimeZone.inDaylightTime(Date date)
> 
> For example, 
> 
> 
> String someID = null;
> TimeZone tz1 = TimeZone.getTimeZone(someID);
> ``` 
> 
> throws a `NullPointerException`
> 
> However this is not documented in the API docs in the form of a _throws:_ section.
> 
> This change updates the documentation to make this apparent.
> 
> Aditionally, updates the javadoc of SimpleTimeZone.inDaylightTime(Date date) to inherit the _ at throws:_

Justin Lu has updated the pull request incrementally with two additional commits since the last revision:

 - Abstract may throw NPE, static will throw, instance use @implspec
 - Add ImplNote for non-abstract instance methods

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/11888/files
  - new: https://git.openjdk.org/jdk/pull/11888/files/a8059d50..145c5929

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11888&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11888&range=03-04

  Stats: 13 lines in 1 file changed: 9 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/11888.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11888/head:pull/11888

PR: https://git.openjdk.org/jdk/pull/11888