# Class PreferenceChangeEvent

java.lang.Object
java.util.EventObject
java.util.prefs.PreferenceChangeEvent

All Implemented Interfaces:
  `Serializable`

public class PreferenceChangeEvent extends EventObject
An event emitted by a `Preferences` node to indicate that a preference has been added, removed or has had its value changed.

Note, that although PreferenceChangeEvent inherits Serializable interface from EventObject, it is not intended to be Serializable. Appropriate serialization methods are implemented to throw NotSerializableException.

Since:
  1.4
See Also:
  - `Preferences`
  - `PreferenceChangeListener`
  - `NodeChangeEvent`

- ## Field Summary

  ### Fields declared in class EventObject

  `source`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `PreferenceChangeEvent(Preferences node, String key, String newValue)`
  Constructs a new `PreferenceChangeEvent` instance.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `String`
  `getKey()`
  Returns the key of the preference that was changed.
  `String`
  `getNewValue()`
  Returns the new value for the preference.
  `Preferences`
  `getNode()`
  Returns the preference node that emitted the event.

  ### Methods declared in class EventObject

  `getSource, toString`

  ### Methods declared in class Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

- ## Constructor Details

  - ### PreferenceChangeEvent

    public PreferenceChangeEvent(Preferences node, String key, String newValue)
    Constructs a new `PreferenceChangeEvent` instance.
    Parameters:
      `node` - The Preferences node that emitted the event.
      `key` - The key of the preference that was changed.
      `newValue` - The new value of the preference, or `null` if the preference is being removed.

- ## Method Details

  - ### getNode

    public Preferences getNode()
    Returns the preference node that emitted the event.
    Returns:
      The preference node that emitted the event.

  - ### getKey

    public String getKey()
    Returns the key of the preference that was changed.
    Returns:
      The key of the preference that was changed.

  - ### getNewValue

    public String getNewValue()
    Returns the new value for the preference.
    Returns:
      The new value for the preference, or `null` if the preference was removed.