A list of lists in Java is a data structure that represents a collection of lists, where each list is an element of the outer list. You can create a list of lists in Java using the ArrayList class or the LinkedList class, which are part of the Java Collection Framework.
Here is an example of how to create a list of lists in Java using the ArrayList class:
List<List<Integer>> listOfLists = new ArrayList<>(); // Add lists to the list of lists listOfLists.add(Arrays.asList(1, 2, 3)); listOfLists.add(Arrays.asList(4, 5, 6)); listOfLists.add(Arrays.asList(7, 8, 9)); // Print the list of lists System.out.println(listOfLists);
In this example, the listOfLists variable is defined as a List of List objects, and the ArrayList class is used to instantiate the list of lists. The add method is used to add lists to the list of lists, and the Arrays.asList method is used to create lists from arrays of integers. The System.out.println method is used to print the list of lists to the console.
You can use this approach to create a list of lists in Java by defining a list of lists and using the add method to add lists to the list of lists. You can also customize this approach by using different types of lists, such as lists of strings or lists of objects, or by using different methods to add lists to the list of lists.
Note that you can also create a list of lists in Java using the LinkedList class, which is another implementation of the List interface that is based on a linked list data structure. To create a list of lists using the LinkedList class, you can use the same approach as the one described above, but you need to use the LinkedList class instead of the ArrayList class to instantiate the list of lists.