<Swing Dev> RFR: 5015261: JInternalFrame causes NPE [v3]

[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 one additional commit since the last revision:

  Spec 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/0c96a6e3..f69c24a1

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=4989&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=4989&range=01-02

  Stats: 2 lines in 1 file changed: 2 ins; 0 del; 0 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