Java Binary Trees

Question

Why isn't it working?

----------------------------------------------------------

//adds a new Node to the tree (in a way of a Binary Search tree):
public void add(int data){
insert(this.root, data);
}

private void insert(Node node, int data){
if (node == null){

//stops the recursion, some node will have to be null sometime..
//also sets the actual real root of the tree a value... :
node = new Node(data);

}else if(node.getData() > data){

//left side of tree:
insert(node.getLeft(), data);

}else if(node.getData() < data){

//right side of tree:
insert(node.getRight(), data);

}
}

Answer 1

node == null
node = new object
but node and object inside are lost in the end of method