NullPointer adding an item to a LinkedList

Hello,

I am trying to perform the following operation:

Code:

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temp[WhichPositionInList].add(posPlusVal);

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Just before doing so, I am doing a println to verify the size of my LinkedListArray (temp), the index that im adding at(WhichPostionInList), and the contents of my string (posPlusVal). Any ideas why I could be getting a null pointer?

Either temp or temp[WhichPositionInList] or possibly posPlusVal is null. Difficult to tell without seeing more code.

thats the frustrating part, I have:

Code:

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System.out.println("adding at position: "+WhichPositionInList);
                      System.out.println("temp size is: "+temp.length);
                      System.out.println("posPlusVal is: "+posPlusVal);
                      temp[WhichPositionInList].add(posPlusVal);

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All 3 of my values return what I expect:

WhichPositionInList = 0;
temp size = 2;
posPlusVal ="10 5";

Quote:

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Originally Posted by sehudson

All 3 of my values return what I expect:

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But you haven't tested the most important one.

Code:

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System.out.println(temp[WhichPositionInList]);

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well....I thought I was adding an element to the WhichPositionInList(th) list in my array?

so I guess what I'm saying is, if I have:

LinkedListArray myArray = new LinkedList[4];

when I do:

myArray[somePosition].add(String) it shouldnt matter whats in the list, im just appending a node, I didnt think you had to initialize each list in the listARray

figured it out...
I have to create the lists individually, and I was trying to stuff a string into a list that hadnt been created..duh.

Exactly.

You were doing the equivalent of:

Code:

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String[] words = new String[5];
System.out.println(words[0]);

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and expecting "blue" to be displayed.