java List of Strings to Array of Strings

Question

I want to know if it's possible to convert a Java List of Strings to an array of Strings:

I tried this:

List<String> products = new ArrayList<String>();
//some codes..
String[] arrayCategories = (String[]) products.toArray();

but it gives me an exception message:

java.lang.ClassCastException: java.lang.Object[] cannot be cast to java.lang.String[]

Problem here is not the Array conversion, but wrong use of [] on new ArrayList[String]() which should be new ArrayList().. I was about to answer but you guys closed this.. — mico, Sep 11 '13 at 10:52
hmmm. now that my edit is wrong, that is corrected. May it remain closed. — mico, Sep 11 '13 at 10:56

score 6 · Accepted Answer · answered Sep 11 '13 at 10:44

6

String[] array = products.toArray(new String[products.size()]);

answered Sep 11 '13 at 10:44

RaceBase

it gaves me the same Exception – Mouad EL Fakir Sep 11 '13 at 10:47
@MouadELFakir, then you might be doing something else wrong. Post your code to check what you are messing up – RaceBase Sep 11 '13 at 10:48
yeah thanks i just figured out what i was missig, i just forget to fill my products list i let it empty, it s working now just fine, thank u ;) – Mouad EL Fakir Sep 11 '13 at 10:51

score 3 · Answer 2 · edited May 23 '17 at 12:13

3

Use

String[] arrayCategories = products.toArray(new String[products.size()]);

products.toArray() will put list values in Object[] array, and same as you cant cast object of super type to its derived type like

//B extands A
B b = new A();

you can't store or cast Object[] array to String[] array so you need to pass array of exact type that you want to be returned.

Additional info here.

edited May 23 '17 at 12:13

Community

answered Sep 11 '13 at 10:44

Pshemo

score 0 · Answer 3 · answered Sep 11 '13 at 10:45

0

Try

List<String> products = new ArrayList<String>();
        String[] arrayCategories = products.toArray(new String[products.size()]);

answered Sep 11 '13 at 10:45

newuser

score 0 · Answer 4 · answered Sep 11 '13 at 10:46

0

This should do the trick. You got an typo in the first line.

List<String> products = new ArrayList<>();
String[] array = (String[]) products.toArray();

answered Sep 11 '13 at 10:46

4 Answers4