//Get rows size matrix
matrix.length;
//Get columns size of matrix
matrix[0].length;
public static void main(String[] args) {
int[][] foo = new int[][] {
new int[] { 1, 2, 3 },
new int[] { 1, 2, 3, 4},
};
System.out.println(foo.length); //2
System.out.println(foo[0].length); //3
System.out.println(foo[1].length); //4
}