prefer modern collection APIs

Use modern collection creation methods instead of legacy alternatives for improved readability and conciseness. Replace older patterns with their modern equivalents:

• Use List.of() instead of Arrays.asList() or Collections.singletonList()
• Use Set.of() instead of new HashSet<>(Arrays.asList(...))
• Use .toList() instead of .collect(Collectors.toList())
• Use Collections.emptyList() → List.of() when creating empty immutable lists

Example transformations:

// Before
List<String> items = Arrays.asList("a", "b", "c");
Set<String> permissions = new HashSet<>(Arrays.asList("READ", "WRITE"));
List<String> results = stream.collect(Collectors.toList());

// After  
List<String> items = List.of("a", "b", "c");
Set<String> permissions = Set.of("READ", "WRITE");
List<String> results = stream.toList();

Modern collection APIs are more concise, expressive, and create immutable collections by default, which helps prevent accidental modifications and improves code safety. They also eliminate the need for intermediate collection creation steps, making the code more direct and readable.