Remove redundant conditions and enhance safety with List.of() method

[dukbong]

• Revised the portion where null check was performed after Assert.notNull(), eliminating redundant null checks
• Enhanced code safety by replacing Arrays.asList() with List.of() to create immutable lists

[sbrannen]

@dukbong, please refrain from opening PRs and then closing them and replacing them with additional PRs, since this introduces unnecessary noise in the issue tracker.