What is Null in Java?

[Nagaraj Shivaklara]

Hi,

I want to know about null. Is it an Object? Does it has size? What actually in real applications null is???

Thanks
Nagaraj

[Mohamed Sanaulla]

null is definitely not an object. Its some value that is not existent.

[Darryl Burke]

From the JLS

3.10.7 The Null Literal
The null type has one value, the null reference, represented by the literal null, which is formed from ASCII characters. A null literal is always of the null type.

NullLiteral:
null

4.12.5 Initial Values of Variables
:
:
:

For all reference types (§4.3), the default value is null.

[William Brogden]

Given that all Java memory allocation sets the locations to zero, the value in memory for a null reference is zero.

Not something you should worry about or try to fool with.

Bill

[Jesper de Jong]

William Brogden wrote:Given that all Java memory allocation sets the locations to zero, the value in memory for a null reference is zero.

If you set a variable to null, then what the actual bits of the reference in memory look like depends on JVM implementation details. It doesn't necessarily have to be zeroes. But it's not something you need to be concerned about, because you can't access the direct value of a reference variable anyway.

[Rob Spoor]

In Visual Basic, the equivalent value of null is called Nothing. I find that name more descriptive than null.

[Bear Bibeault]

Of the synonyms for "nothing" shown by thesaurus.com, the keywords I'd have preferred are: naught, nihility, zilch , or (my favorite) annihilation.

[Randall Twede]

to answer your implied question. we sometimes set things to null in our programs to "erase"(delete) them.

or (my favorite) annihilation.

ah yes, Total Annihilation, one of my all time favorite games.