Some of the important points to remember while using Java

Collections Framework are:

1. Interfaces: For Collections, we should write code with

generic interfaces instead of concrete implementation. Due

to this we maintain the flexibility of changing the

implementation at a later point of time.

2. Generics: We should use Generics for type-safety and to

avoid ClassCastException at runtime.

3. Collections: It is recommended to use Collections utility

class for algorithms and various other common methods

for Collections.

4. Right Type: We have to choose the right type of Java

collection based on our need. If size is fixed, we can use

Array over ArrayList. If we do not want duplicate

elements we use Set.

If we need the ability to iterate the elements of a Map in

the order of insertion then we use a TreeMap.

5. Initial Size: In some collection classes we can specify the

initial size/capacity. Therefore we should have an estimate

of number of elements in a Collection before deciding the

right collection type. We can use it to avoid rehashing or

resizing.

6. Map: We should use immutable classes provided by Java

as key elements in a Map

https://www.javatpoint.com/collections-in-java#:~:text=The%20Collection%20in%20Java%20is,a%20single%20unit%20of%20objects.