Fix errorprone warnings

[inv-jishnu]

Description

This PR fixes error prone and java doc warnings and renamed logger param used from LOGGER to logger.
This PR was created based on following feedback from PR #2591.

• Add import log classes and utils #2591 (comment)
• Add import log classes and utils #2591 (comment)

Related issues and/or PRs

#2591

Changes made

I have made the following changes

• Renamed LOGGER to logger
• Changed assert to assertThat
• Added SAME_NAME_BUT_DIFFERENT to ignore patterns that need to be ignored for data loader core project
• Added suppress warning for SameNameButDifferent and MissingSummary and a few more.
• Fixed few warning with minor code changes
• Removed and unused class and a method

Checklist

The following is a best-effort checklist. If any items in this checklist are not applicable to this PR or are dependent on other, unmerged PRs, please still mark the checkboxes after you have read and understood each item.

• I have commented my code, particularly in hard-to-understand areas.
• I have updated the documentation to reflect the changes.
• I have considered whether similar issues could occur in other products, components, or modules if this PR is for bug fixes.
• Any remaining open issues linked to this PR are documented and up-to-date (Jira, GitHub, etc.).
• Tests (unit, integration, etc.) have been added for the changes.
• My changes generate no new warnings.
• Any dependent changes in other PRs have been merged and published.

Additional notes (optional)

NA

Release notes

Fix warnings for java doc and error prone