I want to know how to declare a Java array

import java.util.Scanner;

public class ManagerHeight {
    Scanner scan = new Scanner(System.in);

    public static void main(String[] args){
        ManagerHeight manager = new ManagerHeight();
        manager.setData(manager.gradeHeights);
    }
    int[][] gradeHeights = new int[5][];

    gradeHeights[0] = new int[5];
    gradeHeights[1] = new int[4];
    gradeHeights[2] = new int[4];
    gradeHeights[3] = new int[3];
    gradeHeights[4] = new int[5];

    public void setData(int[][] clss){
        for(int i=0; i<4; i++){
            for(int k=0; k<gradeHeights[i].length; k++){
                System.out.println(1+i+"Class"+(1+k)+"What is the height of the student?");
                clss[i][k] = scan.nextInt();
            }
        }
    }
}