My name
is
Jon Skeet

How to replace values in List<interface>

I want to replace all commas in the display name in a List, how can i do it?

 for (int i = 0; i < contacts.size(); i++) {
                if(contacts.get(i).getDisplayName().contains(",")){
                    contacts.get(i).getDisplayName().replace("," , " " );
                    contacts.notify();
                }
            }

Well you need to set the display name, I suspect. Currently you're calling String.replace which creates a new string - but as strings as immutable, the existing display name won't be changed. I suspect you really want:

for (Contact contact : contacts) {
    String displayName = contact.getDisplayName();
    if (displayName.contains(",")) {
        contact.setDisplayName(displayName.replace(",", " ");
        contacts.notify();
    }
}

Or possibly better (single notification):

boolean anyChanged = false;
for (Contact contact : contacts) {
    String displayName = contact.getDisplayName();
    if (displayName.contains(",")) {
        contact.setDisplayName(displayName.replace(",", " ");
        anyChanged = true;
    }
}
if (anyChanged) {
    contacts.notify();
}

Note how unless you're using a list index for something other than getting the value out of the list, your code is cleaner if you use an enhanced for loop as above.

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