fixing Mockito initialization issue

[ansjcy]

Is your feature request related to a problem? Please provide an existing Issue # , or describe.
Currently a lot of unit tests are failing with error:

java.lang.NoClassDefFoundError: Could not initialize class org.mockito.Mockito

We need to fix the mockito-core version to 2.23.0.

reference: mockito/mockito#2568

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Check List

• New functionality includes testing.
  • All tests pass
• New functionality has been documented.
  • New functionality has javadoc added
• Commits are signed per the DCO using --signoff

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[codecov]

Codecov Report

Merging #443 (6703758) into main (53e3b94) will decrease coverage by 0.06%.
The diff coverage is n/a.

❗ Current head 6703758 differs from pull request most recent head 1ffea86. Consider uploading reports for the commit 1ffea86 to get more accurate results

@@             Coverage Diff              @@
##               main     #443      +/-   ##
============================================
- Coverage     76.19%   76.13%   -0.06%     
+ Complexity     2604     2601       -3     
============================================
  Files           304      304              
  Lines         15577    15577              
  Branches       1219     1219              
============================================
- Hits          11869    11860       -9     
- Misses         3210     3217       +7     
- Partials        498      500       +2     

see 5 files with indirect coverage changes