Array 2 Dimensi

import javax.swing.JOptionPane;
public class array{
public static void main(String[]args){

int rais[][]= new int[4][5];
int k=30;
String hasil="";
for (int i=0;i<4;i++){
for (int j=0;j<5;j++){
rais[i][j]=k-- ;
}
}
for (int i=0;i<4;i++){
for (int j=0;j<5;j++){
hasil +=(rais[i][j]+" ");
}
hasil +="\n";
}
JOptionPane.showMessageDialog (null, hasil);
System.exit(0);
}
}