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How to convert string ArrayList object to String array object in Java?

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5 Answers

up vote 193 down vote accepted 
List<String> list = ..;
String[] array = list.toArray(new String[list.size()]);

The toArray() method without passing any argument returns Object[]. So you have to pass an array as an argument, which will be filled with the data from the list, and returned. You can pass an empty array as well, but you can also pass an array with the desired size.

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Thank you for your help – Alex Oct 28 '10 at 12:30
1  
Does the size of the argument make any difference? – Thorbjørn Ravn Andersen May 15 '12 at 13:09
5  
it saves one more array instnatiation – Bozho May 15 '12 at 13:28
It shows this warning in logcat: Converting to string: TypedValue{t=0x12/d=0x0 a=3 r=0x7f050009} – Adil Malik Jun 19 at 12:40
up vote 2 down vote

This is enough:

int[] d = new int[list.size()];

for (int i = 0; i < list.size(); i++) {
    d[i] = list.get(i);
}
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Except that we have Strings, not ints. – Teepeemm Sep 18 at 21:14
up vote 1 down vote 
ArrayList<String> arrayList = new ArrayList<String>(); 
Object[] ObjectList = arrayList.toArray();
String[] StringArray = Arrays.copyof(ObjectList,ObjectList.length,String[].class);
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up vote 0 down vote 
List <String> list = ...
String[] array = new String[list.size()];
int i=0;
for(String s: list){
  array[i++] = s;
}
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2  
This works, but isn't super efficient, and duplicates functionality in the accepted answer with extra code. – Alan Delimon Feb 8 at 15:26

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