Observer (Java SE 9 & JDK 9 )

Deprecated.
This interface has been deprecated. See the Observable class for further information.
```
@Deprecated(since="9")
public interface Observer
```
A class can implement the Observer interface when it wants to be informed of changes in observable objects.

Since:

1.0

See Also:

Observable

Method Summary

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

- Method Detail
  - update
```
void update(Observable o,
            Object arg)
```
    Deprecated.
    
    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.