Avoid inserting duplicate in array list

Question

I have a method and I want avoid inserting duplicates in my arraylist which already has data in it. I am not sure if this is right:

 private static Kar karNameExist(Kar kar, ArrayList<Kar> karList) {
    if (karList.contains(kar.getInsertKar())){
        System.out.println(“Kar name exists”);
    }
return kar;
}

Have you tried it? It will be faster to try it than to ask here and wait for answers. — Jim Garrison, Sep 25 '13 at 20:46

score 1 · Answer 1 · answered Sep 25 '13 at 20:46

1

You can LinkedHashSet instead of ArrayList to avoid duplicate entry

answered Sep 25 '13 at 20:46

Shamim Ahmmed

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score 0 · Answer 2 · answered Sep 25 '13 at 20:49

0

If you have ArrayList<Kar>, you want to say karList.contains(kar) to check if kar is already contained in the list. To make this work, you must implement proper hashCode() and equals(Object) in your Kar class (so ArrayList "knows" how to properly compare objects of type "Kar"

answered Sep 25 '13 at 20:49

Gyro Gearless

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Can yoiu please help me on this for coding? I am novice to java. – user2766131 Sep 26 '13 at 13:46

Avoid inserting duplicate in array list

2 Answers2