[ZEPPELIN-6038] Unification of the Logger variable

[ParkGyeongTae]

What is this PR for?

I discovered that the Logger variable differs across files. I want to standardize the Logger variable as "LOGGER" in all files. Please let me know if there are any additional parts that need to be addressed.

What type of PR is it?

Improvement

Todos

• - log -> LOGGER
• - LOG -> LOGGER
• - logger -> LOGGER
• - _LOGGER -> LOGGER

What is the Jira issue?

• https://issues.apache.org/jira/browse/ZEPPELIN-6038

How should this be tested?

• CI
• Build and run the Zeppelin project

Screenshots (if appropriate)

Questions:

• Does the license files need to update? No.
• Is there breaking changes for older versions? No.
• Does this needs documentation? No.

[Reamer]

Please ensure that the logger is also private static final.

[ParkGyeongTae]

@Reamer I have set all logger constants to private static final. Please review this.

[Reamer]

Thank you for your contribution. Found some minor issues and a major issue.
Files within zeppelin-interpreter/src/main/java/org/apache/zeppelin/interpreter/thrift must not be edited. These files are automatically generated.

[Reamer]

LGTM