2 dimensional arraylist java code example

Example 1: java two dimensional arrays

int[][] multiples = new int[4][2];     // 2D integer array with 4 rows 
                                          and 2 columns
String[][] cities = new String[3][3];  // 2D String array with 3 rows 
                                          and 3 columns

Example 2: 2d arraylist in java

int vertexCount = 3;
ArrayList<ArrayList<Integer>> graph = new ArrayList<>(vertexCount);
//Next, we'll initialize each element of ArrayList with another ArrayList:

for(int i=0; i < vertexCount; i++) {
    graph.add(new ArrayList());
}