Assign first element in multidimensional array to one dimensional array

Question

I am trying to add the first element of each array in the two-dimensional array folderArray into a one dimensional array called tempArray as can be seen in the code shown below. However I am getting a null pointer exception from the tempArray. How can I fix this?

    int listLength = folderArray.length;
    String tempArray[] = null;
    for(int x = 0; x<listLength;x++){
        tempArray[x] = folderArray[x][0];
    }

@ZouZou I cant use the tempArray inside the for loop without initializing it to null or else i get an error — , Mar 31 '14 at 11:08
But what do you think initializing it to `null` does? See also http://stackoverflow.com/questions/218384/what-is-a-null-pointer-exception — Alexis C., Mar 31 '14 at 11:16

score 3 · Accepted Answer · answered Mar 31 '14 at 11:08

3

You have to initialise your tempArray before you can assign anything to its elements:

String tempArray[] = new String[listLength];

is a good start (instead of String tempArray[] = null;)

answered Mar 31 '14 at 11:08

Aleks G

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score 1 · Answer 2 · answered Mar 31 '14 at 11:06

1

Because you are assigning tempArray[] as null

Change it as,
String tempArray[] = new String[listLength];

answered Mar 31 '14 at 11:06

Rakesh KR

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Assign first element in multidimensional array to one dimensional array

2 Answers2