CODEWITHSUNDEEP
java
Saikat
Saikat

Reputation: 1219

The array size in Java is fixed after declaration?

I wanted to know if the Java arrays are fixed after declaration. When we do:

int a[10];

and then can we do:

a = new int [100];

I am unsure if the first statement already allocates some memory and the second statement allocates a new chunk of memory and reassigns and overwrites the previous reference.

Upvotes: 1

Views: 24508

Answers (4)

Ramesh Kumar Chikoti
Ramesh Kumar Chikoti

Reputation: 356

Array has fixed length but if you want the array size to be increased after this:

 private Object[] myStore=new Object[10];

In normal way you have to create another array with other size and insert again all element by looping through the first array,but arrays class provide inbuild method which might be useful

myStore = Arrays.copyOf(myStore, myStore.length*2);

Upvotes: 1

Ivan Mushketyk
Ivan Mushketyk

Reputation: 8295

Array have fixed length that is determined when you create it. If you want a data structure with variable length take a look at ArrayList or at LinkedList classes.

Upvotes: 1

npinti
npinti

Reputation: 52185

Yes it is:

The length of an array is established when the array is created. After creation, its length is fixed.

Taken from here.

Also, in your question the first scenario: int a[10] is syntactically incorrect.

Upvotes: 9

Pablo Santa Cruz
Pablo Santa Cruz

Reputation: 181290

The second statement allocates a new chunk of memory, and the previous reference will eventually be garbage collected.

You can see it by yourself using a java debugger. You will notice that a will point to a different location after the second statement executes.

Good luck with your H.W.

Upvotes: 2

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