code cleanup

[cmonkey]

Ⅰ. Describe what this PR did

Ⅱ. Does this pull request fix one issue?

Ⅲ. Why don't you add test cases (unit test/integration test)?

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[codecov-io]

Codecov Report

Merging #1541 into develop will decrease coverage by <.01%.
The diff coverage is n/a.

@@              Coverage Diff              @@
##             develop    #1541      +/-   ##
=============================================
- Coverage      46.45%   46.44%   -0.01%     
  Complexity      1692     1692              
=============================================
  Files            347      347              
  Lines          12719    12719              
  Branches        1591     1591              
=============================================
- Hits            5908     5907       -1     
  Misses          6171     6171              
- Partials         640      641       +1

Impacted Files	Coverage Δ	Complexity Δ
...server/store/file/FileTransactionStoreManager.java	47.03% <0%> (-0.35%)	19% <0%> (ø)

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[xingfudeshi]

LGTM.

[slievrly]

Modify the pr title to describe the problem briefly and accurately

[xingfudeshi]

Modify the pr title to describe the problem briefly and accurately

It should be code cleanup.

[lovepoem]

LGTM