Jesper Young wrote:Welcome to JavaRanch.
To me, that sentence is quite clear - if you create your own collection class, it doesn't need to implement all methods; some are optional, and if you don't need them, you should throw an UnsupportedOperationException from them.
Can you provide some more context, or explain in more detail what it is exactly that you don't understand?
Umesh Vajpai wrote:
Thanks.What i want to know is about interface rule.To implement a interface it is must to implement all methods then how could we can do it as collection is interface.can you explain it in more detail.