Collections

[Suresh KumarPandey]

String[] arr = { "Java", "Champ", "." };
List<String> list = (List<String>) Arrays.asList(arr);
arr[2] = ".com"; // line 210.
for (String word : list) {
System.out.print(word);
}
Can any one explain why it is printing JavaChamp.Com ,why not JavaChamp. because arr[2] is being created when arr[2]was ".";

[nir sharma]

arr[2] = ".com"; // line 210.

because of the above mentioned line, if you remove that you will get the result that you expect.

PS: use code tag for code.

[Seetharaman Venkatasamy]

 

Suresh KumarPandey wrote:why not JavaChamp. because arr[2] is being created when arr[2]was ".";

You are replacing 2nd index value(".") by .com . hence result . the key point is here you are not changing the size of the array/list

[Danjel Nyberg]

Returns a fixed-size list backed by the specified array. (Changes to the returned list "write through" to the array.) This method acts as bridge between array-based and collection-based APIs, in combination with Collection.toArray(). The returned list is serializable and implements RandomAccess.

/Danjel

[Suresh KumarPandey]

hii thanks for the reply
what i am not getting is when we are creating the list array is having "."
after creating the list why changing arr[2] changes the answer

[Henry Wong]

 

Suresh KumarPandey wrote:hii thanks for the reply
what i am not getting is when we are creating the list array is having "."
after creating the list why changing arr[2] changes the answer

Daniel already quoted the reason directly from the Javadoc .... what is it about the response that you don't understand???

http://docs.oracle.com/javase/6/docs/api/java/util/Arrays.html#asList%28T...%29

Henry

[Himai Minh]

Hi Suresh KumarPandey buddy,
Read Kathy's study guide about TreeMap. There is a section about backed collection.
Backed collection means when a collection change, its backed collection changes also.

To me, it seems like list is a backed storage of arr. So, any change in arr will affect list or vice-versa. You can try to change any string in list to see if the change is shown in arr.
Try to do this:

list.add("Test");

I am sure it will output a runtime exception. Because arr is defined as size 3 at the beginning. You tried to add one more string to the list, but arr cannot increase its size.

[Suresh KumarPandey]

Thanks i got it