Multidimentional Array Problem

[Sheetal Kaul]

Hi,

This program is is not giving any problem at compile time, bt at run time nullPointerException is coming,

 
public class Example5 {
 
public static void main(String args[]) {

String str [][][][] =new String[5][5][][];
 
        
 
        for(int i=0;i<3;i++)
 
            for(int j=0;j<3;j++)
 
                for(int k=0;k<3;k++)
 
                    for(int l=0;l<3;l++)
 
                    {
 
                        System.out.println("out");
 
                        str[i][j][k][l]=" "+i+j;
                        
                        System.out.println("out1");
 
                        
 
                    }
 
        for(int i=0;i<3;i++)
 
            for(int j=0;j<3;j++)
 
                for(int k=0;k<3;k++)
 
                    for(int l=0;l<3;l++)
 
                          System.out.println(str[i][j][k][l]);
 
 
}
}

please explain

Sheetal

[ May 03, 2005: Message edited by: Sheetal Kaul ]

(

tags added for clarity)
[ May 03, 2005: Message edited by: Barry Gaunt ]

[Amit Das]

Hi Sheetal,

thats pretty obvoius that its gonna throw a NullPointerException as u've defined and constructed a 4d array of size 5(referenced by ref variable str).....u must be knowing this the only condition required to initialize an n-d array so that all the elements are initialized to their default, whatsoever, after contructuion of the topmost array in the n-d array....
but u have also created a 3d array(size is 5).....now null pointer comes because u are trying to assign a value to lowest array in the 5d array which is not created at all(otherwise it will give ArrayIndexOutOfBoundsException)....its just a null(not pionting to anything)
so as a result u get a NullPointerException......and by the way its a Runtime exception which u'll never get at compile time... ;-)

hope its clear..
if not feel free to get back

amit