Package org.apache.commons.lang3

Class ObjectUtils.Null

java.lang.Object

org.apache.commons.lang3.ObjectUtils.Null

All Implemented Interfaces:

Serializable

Enclosing class:

ObjectUtils

public static class ObjectUtils.Null
extends Object
implements Serializable

Class used as a null placeholder where null has another meaning.

For example, in a HashMap the HashMap.get(Object) method returns null if the Map contains null or if there is no matching key. The null placeholder can be used to distinguish between these two cases.

Another example is Hashtable, where null cannot be stored.

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
private static final long	serialVersionUID	Required for serialization support.

Constructor Summary

Constructors

Constructor	Description
Null()	Restricted constructor - singleton.

Method Summary

Modifier and Type	Method	Description
private Object	readResolve()	Ensure Singleton after serialization.

Methods inherited from class java.lang.Object

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

Field Details

serialVersionUID

private static final long serialVersionUID

Required for serialization support. Declare serialization compatibility with Commons Lang 1.0

See Also:

• Serializable
• Constant Field Values

Constructor Details

Null

Null()

Restricted constructor - singleton.

Method Details

readResolve

private Object readResolve()

Ensure Singleton after serialization.

Returns:

the singleton value