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JAVA linked list constructor always returns null

I've been working on a character sequence (analogous to a string) implemented as a linked list. Each node in the list consists of three fields: data (i.e., what character it represents), value (i.e., how many times it is repeated in a row) and next (i.e., what node it is followed by). One of the constructors "translates" a string into a list as such. However, it happens to always return a null list, as the output of the code

private static void StringToNode (String s, int i, int j,CharNode head)
{
    head=new CharNode(s.charAt(i),j,null);
    if (i+1<s.length()&&s.charAt(i+1)==s.charAt(i))
    {
        StringToNode(s, i+1, j+1, head);
    }
    else if (i+1<s.length()&&s.charAt(i+1)!=s.charAt(i))
    {
        StringToNode(s,i+1,1,head.getNext());
    } 
}
public StringList(String s)
{
    if (s.length()==0)
    _head=null;
    else
    StringToNode(s,0,1,_head);
    if (_head==null)
    System.out.println("Rats!");
}

is Rats! I can't come up with any reason for this code to fail. So help will be greatly appreciated.

Reply 1

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