optimize: Generated instances that were not actually used when the class was loaded

[ph3636]

…aded

Ⅰ. Describe what this PR did

optimize: Generated instances that were not actually used when the class was loaded

Ⅱ. Does this pull request fix one issue?

#2350

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 #2364 into develop will decrease coverage by <.01%.
The diff coverage is 100%.

@@              Coverage Diff              @@
##             develop    #2364      +/-   ##
=============================================
- Coverage      51.73%   51.72%   -0.01%     
+ Complexity      2667     2664       -3     
=============================================
  Files            518      518              
  Lines          16806    16805       -1     
  Branches        2031     2031              
=============================================
- Hits            8694     8693       -1     
  Misses          7294     7294              
  Partials         818      818

Impacted Files	Coverage Δ	Complexity Δ
.../datasource/undo/parser/FastjsonUndoLogParser.java	90% <100%> (ø)	5 <3> (ø)	⬇️
...atasource/undo/parser/ProtostuffUndoLogParser.java	60% <100%> (+0.67%)	5 <2> (ø)	⬇️
...source/undo/mysql/keyword/MySQLKeywordChecker.java	98.91% <100%> (-0.01%)	5 <0> (-1)
...tasource/sql/struct/cache/MysqlTableMetaCache.java	82.55% <100%> (ø)	10 <0> (ø)	⬇️
...o/postgresql/keyword/PostgresqlKeywordChecker.java	89.52% <100%> (ø)	7 <0> (-1)	⬇️
...rce/sql/struct/cache/PostgresqlTableMetaCache.java	79.54% <100%> (ø)	10 <0> (-1)	⬇️
...m/datasource/undo/parser/JacksonUndoLogParser.java	71.95% <100%> (ø)	8 <3> (+1)	⬆️
...urce/undo/oracle/keyword/OracleKeywordChecker.java	96.99% <100%> (-0.03%)	11 <0> (-1)

[slievrly]

LGTM

[zjinlei]

LGTM