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```
public interface Observer
```
A class can implement the Observer interface when it wants to be informed of changes in observable objects.

Since:

JDK1.0

See Also:

Observable

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`update(Observable o, Object arg)`	This method is called whenever the observed object is changed.

- Method Detail
  - update
```
void update(Observable o,
            Object arg)
```
    This method is called whenever the observed object is changed. An application calls an Observable object's notifyObservers method to have all the object's observers notified of the change.
    
    Parameters:
    
    o - the observable object.
    
    arg - an argument passed to the notifyObservers method.

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Interface Observer

Method Summary

Method Detail

update