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?

Answer 1

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.