I'm working on adding JUnit test to an enterprise solution's web services. My question is; how do I - if possible - mock the ERP system in the JUnit tests?

For example I have a `getOrders(Connection con, String customerId)` method. It, however, makes one call to the ERP system to list all orders like:

```
public List<Order> getOrders(Connection con, String customerId) {
  // Call ERP system
  orders = con.fetchOrders(customerId);

  // Manipulate result
  orders...

  return orders;      
}

```

Any way to mock the ERP connection?