public boolean hasNext() {
        if (root1 != null || stack1.size() > 0 || root2 != null
                || stack2.size() > 0) {
            return true;
        }
        return false;
    }
Next inorder iterator of two trees.
Merging tree to print one result
src/com/interview/tree/NextInorderSuccessorOfTwoTree.java