When are array initialized in Java?

Question

When I write this

 String[] fruits = {"Apple", "Pear"};

I would expect that at compile time the array and the strings are created, like it would happen for similar code in C. Is it correct? Are array and their content generally created at compile time or at run-time?

Denys Séguret · Accepted Answer · 2012-11-12 09:51:50Z

8

Arrays, which are objects in Java, are created. This can only occur at runtime.

Note that many objects are created in a Java program, and your object creations occurs only after the VM itself is initialized. One static array initialization isn't going to put a noticeable burden on your performances.

If you don't change the array and you have many instances, be sure to declare it as static :

static String[] fruits = {"Apple", "Pear"};

Note also an important difference with what could be a statically compiled array : the java array is mutable. You can't change its length but you can change its elements (or nullify them). A java array, even final static, isn't really constant.

edited Nov 12, 2012 at 9:51

answered Nov 9, 2012 at 15:39

Denys Séguret

384k90 gold badges813 silver badges780 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

kosa · Accepted Answer · 2012-11-09 15:39:55Z

5

Arrays are special objects in java. So, they will be created at runtime.

As per Java Language Specification

In the Java programming language, arrays are objects (§4.3.1), are dynamically created, and may be assigned to variables of type Object (§4.3.2)

JLS 15.10 provides more information on array creation expressions.

answered Nov 9, 2012 at 15:39

kosa

66.7k15 gold badges134 silver badges170 bronze badges

Collectives™ on Stack Overflow

When are array initialized in Java?

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related