Title: Extend an interface.
Course: Java Programming (Oracle) (10055) > Section: Using Packages and Interfaces

Extension should be written to anticipate multiple uses for the interface and allow users to upgrade. Sample code for an extension follows:

//create an interface
public interface StockWatcher {
final String
sunTicker = "SUNW";
final String oracleTicker = "ORCL";
final String ciscoTicker = "CSCO";
void valueChanged(String tickerSymbol, double newValue);
}