Menu
Is there any Difference between two lines in the following
ArrayList<String> arrName = new ArrayList<String>();
List<String> arrName = new ArrayList<String>();
Thanks for Reply
575
ArrayList allows duplicate values while HashSet doesn't allow duplicates values. Ordering : ArrayList maintains the order of the object in which they are inserted while HashSet is an unordered collection and doesn't maintain any order.
collect(Collectors. toList()); This code says for each member of the list turn it into 4 copies of the item then collect all those as a list and add them to the original list.
The easiest way to remove repeated elements is to add the contents to a Set (which will not allow duplicates) and then add the Set back to the ArrayList : Set<String> set = new HashSet<>(yourList); yourList. clear(); yourList.
In order to copy elements of ArrayList to another ArrayList, we use the Collections. copy() method. It is used to copy all elements of a collection into another. where src is the source list object and dest is the destination list object.
Almost always the second one is preferred over the first one. The second has the advantage that the implementation of the List can change (to a LinkedList for example), without affecting the rest of the code. This is will be difficult to do with an ArrayList, not only because you will need to change ArrayList to LinkedList everywhere, but also because you may have used ArrayList specific methods.
161
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
