List interface in Collection Framework

[Ajay Singh Rathore]

can anyone explain this syntax.

List<List<Integer>> table = new ArrayList<List<Integer>>();

what is the meaning of this syntax.

[Santhi Bharath]

up to my knowledge that is list of integer lists.

tables list contains lists of integers

[Ankit Garg]

Hi Ajayr! Welcome to Javaranch.

Santhi is right. your reference variable table is a list of integer lists.

Lets take a more meaningful example to understand this-

List<List<Planet>> solarSystems = new List<List<Planet>>();

so here we have a list of solar systems, where each solar system has a list of planets. You can add elements to this list as follows

List<Planet> sun = new List<Planet>();
sunPlanets.add(new Planet("Mercury"));
sunPlanets.add(new Planet("Venus"));
sunPlanets.add(new Planet("Earth"));

solarSystems.add(sun);

List <Planet> dogStar = new List<Planet>();
dogStar.add(new Planet("MyPlanet1"));
dogStar.add(new Planet("MyPlanet2"));

solarSystems.add(dogStar);

[Rekha Srinath]

More than the theoretical explanation, the code looks more understanding...Thanks Ankit !!!