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Thread: Hash set

  1. #1
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    Default Hash set

    I have an array 'arr' with integers. I need to display only the unique values. I did this using hash array set and While executing I found an error like this ,

    Exception in thread "main" java.lang.ArrayStoreException: [I
    at java.util.AbstractCollection.toArray(AbstractColle ction.java:171)
    at test.main(test.java:57)

    Here is my logic I used to get unique values,

    Set hashSet = new HashSet(Arrays.asList(arr));
    String[] unique = (String[]) hashSet.toArray(new String[hashSet.size()]);

    Can someone help me on this??

  2. #2
    Iron Lion is offline Senior Member
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    The toArray() method of the collection classes works somewhat unintuitively. The correct syntax is:

    Java Code:
    String[] unique = new String[hashSet.size()];
    hashSet.toArray(unique);

  3. #3
    JosAH's Avatar
    JosAH is offline Moderator
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    Default

    Quote Originally Posted by Iron Lion View Post
    The toArray() method of the collection classes works somewhat unintuitively. The correct syntax is:

    Java Code:
    String[] unique = new String[hashSet.size()];
    hashSet.toArray(unique);
    That's not it: the OP wants to store Integers in a String array (see the [I part in the Exception message).

    kind regards,

    Jos
    cenosillicaphobia: the fear for an empty beer glass

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