Fix possiable NPE

[lonre]

What's the purpose of this PR

NPE in some cases

Which issue(s) this PR fixes:

Fixes #

Brief changelog

XXXXX

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[codecov-commenter]

Codecov Report

Merging #3832 (2e18da2) into master (f9c69db) will decrease coverage by 0.07%.
The diff coverage is 0.00%.

@@             Coverage Diff              @@
##             master    #3832      +/-   ##
============================================
- Coverage     50.16%   50.08%   -0.08%     
+ Complexity     2465     2464       -1     
============================================
  Files           483      483              
  Lines         14922    14921       -1     
  Branches       1520     1520              
============================================
- Hits           7485     7473      -12     
- Misses         6908     6921      +13     
+ Partials        529      527       -2     

Impacted Files	Coverage Δ
.../framework/apollo/core/utils/DeferredLogCache.java	71.42% <0.00%> (-0.41%)	⬇️
...work/apollo/biz/message/DatabaseMessageSender.java	50.00% <0.00%> (-14.59%)	⬇️
...mework/apollo/portal/component/PortalSettings.java	57.81% <0.00%> (-7.82%)	⬇️
...ervice/service/ReleaseMessageServiceWithCache.java	87.05% <0.00%> (+1.17%)	⬆️

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[klboke]

Hello, can you briefly explain what scenarios will cause problems?

[lonre]

Hello, can you briefly explain what scenarios will cause problems?

Hi, in some edge case, such as debugging for the config loading process, that will be longer than 1 minute,

than the log expired and caused the NPE.

IMO, also we should keep all logs, it should not too much

@klboke

[klboke]

LGTM

[lonre]

LGTM

@nobodyiam ping

[nobodyiam]

LGTM