RFR: 8373928: 4 Dangling pointer defect groups in java.c

[Henry Jen]

Fix dangling pointers.

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Commit messages:
 - 8373928: 4 Dangling pointer defect groups in java.c

Changes: https://git.openjdk.org/jdk/pull/29351/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=29351&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8373928
  Stats: 4 lines in 1 file changed: 3 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/29351.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29351/head:pull/29351

PR: https://git.openjdk.org/jdk/pull/29351