RFR: 8294948: Document IllegalArgumetException thrown by URLStreamHandler::parseURL and URLStreamHandler::setURL [v3]

[Daniel Fuchs]

> During the review of JDK-8293590, it was noted that some methods in `URLStreamHandler` were missing an `@throws IllegalArgumentException` clause in their API documentation. 
> 
> This change adds the requested information, and also clarifies throwing `MalformedURLException` from URL constructors.
> 
> The CSR can be reviewed here: https://bugs.openjdk.org/browse/JDK-8294984

Daniel Fuchs has updated the pull request incrementally with one additional commit since the last revision:

  Adding missing @throws NPE

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/10609/files
  - new: https://git.openjdk.org/jdk/pull/10609/files/6b5144cd..4f92fd5b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=10609&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=10609&range=01-02

  Stats: 5 lines in 1 file changed: 4 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/10609.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10609/head:pull/10609

PR: https://git.openjdk.org/jdk/pull/10609