Use class names to access static variables or methods

[lordcheng10]

Motivation

Accessing the static variables and methods of the class through the object reference of this class will increase the cost of the compiler's analysis. A better way is to directly use the class name to access the static variables or methods.

[nicoloboschi]

LGTM

[lordcheng10]

@dlg99 PTAL , thanks!

[lordcheng10]

rerun failed checks

[lordcheng10]

rerun failed checks

[lordcheng10]

rerun failed checks

[lordcheng10]

rerun failed checks

[lordcheng10]

rerun failed checks

[lordcheng10]

rerun failed checks

[dlg99]

tests are failing with

Execution failed for task ':bookkeeper-common:compileTestJava'.
> Could not resolve all files for configuration ':bookkeeper-common:testCompileClasspath'.
   > Could not find log4j:log4j:1.2.27.

which is probably something caused by #2816 nd gradle changes colliding
@RaulGracia @pkumar-singh can you take a look at this?

[pkumar-singh]

This PR from @RaulGracia #2816 should have fixed it. Kindly check @dlg99

[lordcheng10]

This PR from @RaulGracia #2816 should have fixed it. Kindly check @dlg99

@dlg99 @pkumar-singh Thanks for your attention, I merge the master code into my branch and try again。

[lordcheng10]

@hsaputra PTAL , thanks!

[lordcheng10]

PTAL,thanks! @dlg99