Spring Replace Collections.unmodifiableList(new ArrayList(..)) with List.copyOf()

This PR replaces Collections.unmodifiableList() with List.copyOf(). It creates a new immutable list by copying the elements of the given list. Using List.copyOf() results in more readable and prevents unexpected bugs, and makes the code easier to maintain.

Comment From: pivotal-cla

@ssang1105 Please sign the Contributor License Agreement!

Click here to manually synchronize the status of this Pull Request.

See the FAQ for frequently asked questions.

Comment From: pivotal-cla

@ssang1105 Thank you for signing the Contributor License Agreement!

Comment From: ssang1105

@rstoyanchev I found and fix it