在数组上克隆方法是深拷贝还是浅拷贝？

Question

I'm not sure if the following will result in deep or shallow copy?

public void viewImages(final String[] instancesFilename) {

    String[] instances = (String[])instancesFilename.clone();    
}

Is there a simple and fast way to deep copy a string array?

Answer 1

Strings in Java are imutable(Can't change their value). So there is no detectable difference between a deep and shallow copy when copying strings.

And just to further reference: The copy will be shallow but that should not be a problem since strings are imutable.

Oh and funny fact: Strings can't be cloned with the clone method, so if you try to do a deep copy of strings with the clone method, you will get a CloneNotSupportedException.

Answer 2

The array class also has the copyOf method. This is generally what I use for creating copies of arrays. Heres and explanation of all of the differences: http://forum.codecall.net/topic/49450-copying-arrays/

Answer 3

Here is an interesting article discussing using serialization to make deep copies .

The objects in the call graph do need to support serialization however in many business types of 3 Tier applications, that necessity is there.

The article provides a discussion of deep copy and shallow copy with some diagrams.