Avoid inserting duplicate in array list [duplicate]

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;
}

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– Jim Garrison, Commented Sep 25, 2013 at 20:46

Shamim Ahmmed · Accepted Answer · 2013-09-25 20:46:02Z

1

You can LinkedHashSet instead of ArrayList to avoid duplicate entry

answered Sep 25, 2013 at 20:46

Shamim Ahmmed

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Comments

Gyro Gearless · Accepted Answer · 2013-09-25 20:49:31Z

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, 2013 at 20:49

Gyro Gearless

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1 Comment

user2766131 Over a year ago

Can yoiu please help me on this for coding? I am novice to java.

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