jdbc in android, NullPointerException thrown -

public class mainactivity extends actionbaractivity {  string id ; string name ; int price;  private resultset result; private connection con; string url = "jdbc:mysql://localhost:3306/fyp_restaurant"; string username = "root"; string password = "";  @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_main);      try{         class.forname("com.mysql.jdbc.driver").newinstance();      }catch(exception e){         system.err.println("cannot create connection");     }      try{         con = drivermanager.getconnection(url, username, password);          statement statement = con.createstatement();          string query = "select * product";         result = statement.executequery(query);     }catch(exception e){         system.err.println("error");     }      try {         id = result.getstring("id");         name = result.getstring("name");         price = result.getint("price");     }catch (exception e){         system.out.println(e.getmessage());     }       //toast.maketext(getapplicationcontext(), "id" + id + "\nname" + name + "\nprice" + price,toast.length_short).show(); } 

i don't know whether jar file in correct directory - should in libs? using android studio. need add library in android studio?