Spring Boot Microservices application example with step by step guide for beginners

Java9 has additional feature on Collections, based on requirement we need an immutable collections. To create immutable collections we can use of() method on Collection Class.

List<string> names = List.of("Jaya", "Kumar", "Reddy");
         
        //Preserve the elements order
        System.out.println(names);
         
        //names.add("Brian"); //UnsupportedOperationException occurs
         
        //java.lang.NullPointerException
        //List<string> names2 = List.of("Jaya", "Kumar", "Reddy", null);

Set do not allow duplicate elements, where as list has duplicate elements.