Gotchas in Java

These are some pitfalls that took me some time to unravel.

1. I used to think .collect(Collectors.toList()) and .toList() are same and interchangeable.

   But first one creates a mutable list and second one creates a immutable list

            List<Integer> list = new ArrayList<>();
            // Creates a Modifiable List
            list = list.stream().collect(Collectors.toList());
            list.add(1); // This won't throw an error
   
            // Creates an Immutable list
            list = list.stream().toList();
            list.add(1); // This throws an error
   

I will update this blog as soon as I find one.