Create an ArrayList to store HashSet in Java

Question

I have an array of nodes, which is 4000 elements large. During my traversal algorithm, each node will meet other node. I want to create a HashSet to store each node it meets on the way. Each node should has their own HashSet .

Does Java have a construct like this?

<Hashset<Node>>[] res = new Hashset<Node>[4000];

Answer 1

Yes. A generic type parameter may itself be generic , and thus the following is valid:

ArrayList<HashSet<Node>> res=new  ArrayList<HashSet<Node>>();

Note capitalization in the name of java.util.HashSet .