Thread: Stack Overflow

Hey guys, i need to construct text to a linked list and then sort it lexicographically, i used merge sort method for that,
but it triggers stack overflow when going to my split method , and i can't seem to find what's wrong with the recursion.
ideas?

public class TextList {
    WordNode _head;
 
    public TextList () 
    {
        _head = null;    
    }
    public TextList (String text) 
    {
 
        construct(text);
        mergeSort(_head);
    }
    private WordNode construct(String text)
    {
        int i = 0;
        String tmp = "";
        int index = 0;
        if (text != null)
        {
            for (; i < text.length() ; i++ ) 
            {
                if (text.charAt(i) == ' ')
                {
                    index++;
                    _head = new WordNode(tmp);
                    _head.setNext(addText(_head, text.substring(index)));
                    return _head;
                }
                else // charAt i = a characeter
                {
                    tmp += text.charAt(i);
                    index++;
                }
            }  
        }
        _head = null;  
        return _head;
    }
    private WordNode addText(WordNode behind, String text)
    {
        String tmp = "";
        int index = 0;
            while (index < text.length()) 
            {
                if (text.charAt(index) == ' ')
                {
                    WordNode tmpo = new WordNode(tmp);
                    behind.setNext(tmpo);
                    index++;
                    behind = tmpo;
                    tmp = "";
                }
                else // charAt i = a characeter
                {
                    tmp += text.charAt(index);
                    index++;
                }
            }  
        WordNode tmpo = new WordNode(tmp);
        behind.setNext(tmpo);
        return _head;
    }
    private WordNode mergeSort (WordNode node)
    {
        if (node == null || node.getNext() == null)
            return null;
        WordNode list2 = split(node);
        node = mergeSort(node);
        list2 = mergeSort(list2);
        return merge(node, list2);
    }
    private WordNode split(WordNode node)
    {
        if (node == null || node.getNext() == null)
            return null;
        WordNode list2 = node.getNext();
        node.setNext(list2.getNext());
        list2.setNext(split(list2.getNext()));                             <<<<----------- Stack overFlow happens in here
        return list2;
    }
    private WordNode merge(WordNode list1, WordNode list2)
    {
        if(list1 == null)
            return list2;
        if(list2 == null)
            return list1;
        if (list1.getValue().compareTo(list2.getValue()) < 0)
        {
            list1.setNext(merge (list1.getNext(), list2));
            return list1;
        }
        else
        {
            list2.setNext(merge(list1, list2.getNext()));
            return list2;
        }
    }
public String toString() 
    {
        WordNode temp = _head;
        if (temp == null)
            return "";
        return toString(temp, 1, temp.getValue(), "");
    }
    private String toString(WordNode node, int count, String current, String res)
    {
        if (node == null)
            return res;
        if (node.getNext()  == null)
        {
            current = node.getValue();
            res +=  current + "\t" + count + "\n";
            return res;
        }
        if (node.getValue() == node.getNext().getValue())
        {
            count++;
            return toString(node.getNext(), count, current, res);
        }
        else
        {
            current = node.getValue();
            res +=  current + "\t" + count + "\n";
                return toString(node.getNext(), 1, current, res);
        }
 
    }
}

this is my tester :

 
public class Tester {
 
    public static void main(String args[]) {
        TextList List0 = new TextList();
        System.out.println(List0);
        TextList List1 = new TextList("hello nice to meet you my name is ");
        System.out.println(List1);
 
}
 
}

I spared you some other code that i wrote that i think that is irrelevant, and there is another class called WordNode to store data of the node
with getters and setters and somemore.

Thanks!