final array in Java

Question

The following code in Java uses a final array of String and there is no question about it.

final public class Main {   public static final String[] CONSTANT_ARRAY = {"I", "can", "never", "change"};    public static void main(String[] args) {     for (int x = 0; x < CONSTANT_ARRAY.length; x++) {       System.out.print(CONSTANT_ARRAY[x] + " ");     }   } } 

It displays the following output on the console.

I can never change 

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The following code also goes without any question.

final public class Main {   public static final String[] CONSTANT_ARRAY = {"I", "can", "never", "change"};    public static void main(String[] args) {     //CONSTANT_ARRAY={"I", "can", "never", "change"}; //Error - can not assign to final variable CONSTANT_ARRAY.     for (int x = 0; x < CONSTANT_ARRAY.length; x++) {       System.out.print(CONSTANT_ARRAY[x] + " ");     }   } } 

Obviously, the commented line causes the specified error because we are trying to reassign the declared final array of type String.

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What about the following code.

final public class Main {   public static final String[] CONSTANT_ARRAY = {"I", "can", "never", "change"};    public static void main(String[] args) {     CONSTANT_ARRAY[2] = "always";  //Compiles fine.     for (int x = 0; x < CONSTANT_ARRAY.length; x++) {       System.out.print(CONSTANT_ARRAY[x] + " ");     }   } } 

and it displays I can always change means that we could manage to modify the value of the final array of type String. Can we ever modify the entire array in this way without violating the rule of final?

Answer 1

final in Java affects the variable, it has nothing to do with the object you are assigning to it.

final String[] myArray = { "hi", "there" }; myArray = anotherArray; // Error, you can't do that. myArray is final myArray[0] = "over";  // perfectly fine, final has nothing to do with it 

Edit to add from comments: Note that I said object you are assigning to it. In Java an array is an object. This same thing applies to any other object:

final List<String> myList = new ArrayList<String>(): myList = anotherList; // error, you can't do that myList.add("Hi there!"); // perfectly fine.