Refactor: Check equality with literal on lhs

[AlexCai2019]

There are some equals() that are not constant.equals(variable), but variable.equals(constant).
I suggested to always use constant.equals(variable), since it can avoid vary unintentionally bug, such as NullPointerException.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[stleary]

@AlexCai2019 refactoring is not encouraged in this project, but I think in this case it improves the code.
Test coverage is good overall, except for JSONObject removeLeadingZerosOfNumber()

If you get a chance to add some test coverage in the next 3 days, it would be appreciated. Otherwise, I can add something later.

[stleary]

What problem does this code solve?
Improves code safety by checking for string equality with literals on the lhs.

Does the code still compile with Java6?
Yes

Risks
Low

Changes to the API?
No

Will this require a new release?
No

Should the documentation be updated?
No

Does it break the unit tests?
No, but low coverage was found in one method.

Was any code refactored in this commit?
This commit is a refactor.

Review status
APPROVED

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