[jdk20] RFR: 8301989: new javax.swing.text.DefaultCaret().setBlinkRate(N) results in NPE [v2]

[Alexander Zuev]

> Check if the component is associated with the caret before calling methods from it. Added test case that will make sure that will not happen again.

Alexander Zuev has updated the pull request incrementally with one additional commit since the last revision:

  Fixe copyright year.

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Changes:
  - all: https://git.openjdk.org/jdk20/pull/122/files
  - new: https://git.openjdk.org/jdk20/pull/122/files/81978ac4..bfb308dc

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk20&pr=122&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk20&pr=122&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk20/pull/122.diff
  Fetch: git fetch https://git.openjdk.org/jdk20 pull/122/head:pull/122

PR: https://git.openjdk.org/jdk20/pull/122