Enhance class & function documentation in CircularBuffer.java

[Hardvan]

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized it.
• All filenames are in PascalCase.
• All functions and variable names follow Java naming conventions.
• All new algorithms have a URL in their comments that points to Wikipedia or other similar explanations.
• All new code is formatted with clang-format -i --style=file path/to/your/file.java

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 66.23%. Comparing base (640d823) to head (c8f60d2).

Additional details and impacted files

@@            Coverage Diff            @@
##             master    #5582   +/-   ##
=========================================
  Coverage     66.22%   66.23%           
- Complexity     4428     4430    +2     
=========================================
  Files           606      606           
  Lines         16845    16848    +3     
  Branches       3241     3242    +1     
=========================================
+ Hits          11156    11159    +3     
  Misses         5240     5240           
  Partials        449      449           

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[siriak]

Please fix tests, they never stop

[Hardvan]

I have refactored the test cases and fixed the infinite execution problem.