Diameter of Binary Tree - Better Design

Question

I have written a code for finding diameter of Binary Tree. Need suggestions for the following:

1. Can I do this without using static variable at class level?

Answer 1

public class NodeWrap{
    int height = 0;
    int maxLength = 0;
    public NodeWrap(int h, int m){
        height = s;
        maxLength = m;
    }
}


public NodeWrap getDiameter(BinaryNode root){
    if(root == null){
        return new NodeWrap(0, 0);
    }

    NodeWrap left = getDiameter(root.left);
    NodeWrap right = getDiameter(root.right);

    int height = Math.max(left.height + right.height) + 1;

    int maxLength = Math.max(left.maxLength, right.maxLength);
    if(left.height != 0 && right.height != 0){
        maxLength = Math.max(left.height + right.height + 1, maxLength);
    }
    return new NodeWrap(singleLength, maxLength);
}