5 replies to this topic

[isuru]

I created this testing code. But I get nullPointerException, I may being a fool.
Can anyone clarify this for me.

package test;


import java.io.File;



public class Main {


   public long[] getFileSize()

    {

        File file = new File("D:\\new");


        String fileSize[] = file.list();

        long TotalSize[] = null;



        for(int i=0; i<fileSize.length;i++)

        {

            TotalSize[i] = file.getTotalSpace();


        }


        return TotalSize;


    }


    public static void main(String[] args) {

       Main app = new Main();

       app.getFileSize();

    }


}

[Sinipull]

You are attempting to access a part of an array that doesn't exist yet.
right here:
TotalSize[i] = file.getTotalSpace();

TotalSize hasn't been initialized yet. Why are you trying to fill an array of longs with the numbers returned from getTotalSpace method is beyond my understanding...

[isuru]

Sinipull said:

You are attempting to access a part of an array that doesn't exist yet.
right here:
TotalSize[i] = file.getTotalSpace();

TotalSize hasn't been initialized yet. Why are you trying to fill an array of longs with the numbers returned from getTotalSpace method is beyond my understanding...

I need to get a list of arrays... but i think above code gets just numbers.... but i need get list of file last modified.

[wim DC]

isuru said:

I need to get a list of arrays... but i think above code gets just numbers....

A list of arrays is something like:
List<Class[]> listOfArrays .. Which doesn't make much sence here.

isuru said:

but i need get list of file last modified.

What does that has to do with the filesize?

[isuru]

oxano said:

A list of arrays is something like:
List<Class[]> listOfArrays .. Which doesn't make much sence here.


What does that has to do with the filesize?

I am creating file browser. like windows explorer. So I need to put file size in a table with file name...

[Roman Y]

Well I think that you get a null pointer exception becuase you do not specify the length of your array. infact it looks like that you only create a variable to array and point it to null. You should create one like this:

long[] totalSize = new long[size];

if you don't know exactly how long array is going to be you might want to create an arrayList that increases the array-size everytime it hits the borders...