What value is stored in an initialized but empty integer array in Java

Question

I made the following array:

int[] array = new int[9];

This array is initialized, but empty. In that case, what is the value of any index of this array? When I print it out, it gives me 0. Does that mean there is a zero stored in here (like if you had called int x = 0)? Or is it null?

Also, is this the same for any Object array? Is it an empty instance of this object, or is it null?

all 1s. This is basic Java in any 101 book or tutorial. Have you seen the ones on Oracle? http://goo.gl/QiHpsb — tgkprog, Mar 07 '15 at 21:36
I'm voting to close this question as off-topic because it can be trivially found in the documentation. http://docs.oracle.com/javase/tutorial/java/nutsandbolts/datatypes.html — Jeroen Vannevel, Mar 07 '15 at 21:37
@JeroenVannevel are general purpose questions not allowed on SnackOverflow; if so, how would we flag them? — Obicere, Mar 07 '15 at 21:49
possible duplicate of [What is the default initialization of an array in Java?](http://stackoverflow.com/questions/3426843/what-is-the-default-initialization-of-an-array-in-java) — Alexis King, Mar 07 '15 at 23:24

score 0 · Answer 1 · answered Mar 07 '15 at 21:34

0

All elements are initialized to 0.

answered Mar 07 '15 at 21:34

emlai

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score 0 · Accepted Answer · answered Mar 07 '15 at 21:35

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If it is an Array of objects it will be initialized with null, if it's an array of primitive values (like int) it will be initialized with 0. For the non-number primitive boolean it is false and for 'char' it is '\u0000'. For more information, check the table Default Values on the following page:

http://docs.oracle.com/javase/tutorial/java/nutsandbolts/datatypes.html

answered Mar 07 '15 at 21:35

Marv

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and if the primitive is `boolean`, it'll be initialized with `false` value. – Melika Barzegaran Mar 07 '15 at 21:36
@MelikaBarzegaranHosseini I've edited my post accordingly. – Marv Mar 07 '15 at 21:38

score 0 · Answer 3 · answered Mar 07 '15 at 21:37

I copy from Javadocs:

http://docs.oracle.com/javase/tutorial/java/nutsandbolts/datatypes.html

Primitive Data Types : Default Values

Data Type   Default Value (for fields)
byte    0
short   0
int 0
long    0L
float   0.0f
double  0.0d
char    '\u0000'
String (or any object)      null
boolean false

So, for int, it is zero (0)

Arnaud Bertrand · Answer 4 · 2015-03-07T21:45:15.890

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Integer class can be null however "int" type cannot be null.

You can try int x = null; you'll have an error.

Therefore it is created by default to 0 until you change it.

edited Mar 07 '15 at 21:45

answered Mar 07 '15 at 21:37

Arnaud Bertrand

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score 0 · Answer 5 · answered Mar 07 '15 at 21:37

Every value in an int array is initialized to 0 by default. This is something that you can easily try on your own:

    int [] nums = new int [9];

    for (int i = 0; i < nums.length; i++) {
        System.out.println(nums[i]);
    }

Result:

score 0 · Answer 6 · answered Mar 07 '15 at 21:38

0

Here are the default values for the different types in Java:

byte 0

short 0

int 0

long 0L

float 0.0f

double 0.0d

char ‘u0000′

String (or any Object) null

boolean false

As you can see, int defaults to 0.

answered Mar 07 '15 at 21:38

Dermot Blair

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What value is stored in an initialized but empty integer array in Java

6 Answers6