How to create Immutable List in java?

Question

I need to convert mutable list object to immutable list. What is the possible way in java?

public void action() {
    List mutableList =          


        

Answer 1

From Java 10 on, List.copyOf(Collection) can be used to return an unmodifiable list from the given collection. From source code of List.copyOf method:

• if the given collection is an unmodifiable List, List.copyOf() will not create a copy.

• if the given collection is mutable and modified, the returned list will not reflect such modifications. Meaning they are independent.