[Improvement][server] Fix some sonar analyzed bugs (#3415)

* [FIX_BUG][*]fix sonar bugs
fix assert error(assertions always pass)

* fix assert error(assertions always pass)
insert data should judging the success status

* fix assert error(assertions always pass)

* use AtomicReference<Object> to replace unsafe volatile Object

* use AtomicReference<Object> to replace unsafe volatile Object

* lazy initialization holder class Singleton...

* reformat code
judge database operations

* reformat code
judge database operations

* revert

* use ThreadLocalRandom to build random numbers

* reform code

* fix dao test error

* judge database operations