<Swing Dev> RFR: 5015261: JInternalFrame causes NPE [v2]

[Prasanta Sadhukhan]

> JInternalFrame.getDesktopIcon() can be null as setDesktopIcon() can be called with null value. There are many places in JInternalFrame where getDesktopIcon() is accessed without null check which might cause NPE. 
> Added null check for those cases.

Prasanta Sadhukhan has updated the pull request incrementally with two additional commits since the last revision:

 - Remove test
 - Update javadoc clarification

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/4989/files
  - new: https://git.openjdk.java.net/jdk/pull/4989/files/2a2ab50d..0c96a6e3

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=4989&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=4989&range=00-01

  Stats: 73 lines in 2 files changed: 1 ins; 63 del; 9 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4989.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4989/head:pull/4989

PR: https://git.openjdk.java.net/jdk/pull/4989