public class node {
    node left;
    node right;
    String data;

    public node(String data) {
        this.data = data;
    }
}

===

public class tree {

    public static boolean insert(node parent, String data, boolean dir){

        if (dir == true){
            parent.left = new node(data);
            return true;
        }

        parent.right = new node(data);
        return true;
    }
}