Here is an example of generating two-dimensional array.

import java.util.*;

public class twoDimension{
    public static void main(String[] args) { 
        Scanner input=new Scanner(System.in);
        System.out.print("Enter value of i: ");
        int a=input.nextInt();

        System.out.print("Enter value of j: ");
        int b=input.nextInt();

        int[][] a2 = new int[a][b];
        System.out.println("Enter elements of your choice: ");
        for(int i=0 ; i < a2.length ; i++){
          for(int j=0 ; j < a2[i].length ; j++){
          a2[i][j] = input.nextInt();
        }
        }
        for(int i=0 ; i < a2.length ; i++){
            System.out.println();
            for(int j=0 ; j < a2[i].length ; j++){
                System.out.print(a2[i][j]+" ");
            }
        }
    }
}