Hi, I have a wrapper class where it displays contacts related to accounts along with checkboxes. I am adding new records into it with a custom button. I want to add an error message if there are duplicates in record names. Can someone help me to solve this.

//Wrapper Class Code
public class AccountContactWrapper {
    List<Contact> selectedRecords {get;set;}
    public List<WrapperClass> wrapperList {get;set;}
    public List<Account> accList {get;set;}
    public AccountContactWrapper (ApexPages.StandardController stdController) {
        accList = [SELECT Id, Name FROM Account];
        wrapperList = new List<WrapperClass>();
        for(Contact c : [SELECT FirstName, LastName, Phone FROM Contact WHERE AccountId =: ApexPages.currentPage().getParameters().get('id')]) {
            wrapperList.add(new WrapperClass(c));
        }
    }
    //Deleting SelectedRecords
    public void deleteRecords() {
        List<Contact> selectedRecords = new List<Contact>();
        for (WrapperClass wrap : wrapperList) {
            if(wrap.selected==true) {
                selectedRecords.add(wrap.con);
            }
        }
        delete selectedRecords;
    }
    //Creating New Contact Record
    public void createNewContact() {
        wrapperList = createNewContact(wrapperList);
    }
    public List<WrapperClass> createNewContact (List<WrapperClass> insertList) {
        WrapperClass newRecord = new WrapperClass();//To display new Row
        Contact newContactRecord = new Contact();//Creates new Record
        newContactRecord.AccountId = ApexPages.currentPage().getParameters().get('id');
        newRecord.con = newContactRecord;
        insertList.add(newRecord);
        return insertList;
    }
    //Saving New Records
    public void saveRecords() {
        List<Contact> selectedRecords = new List<Contact>();
        for(WrapperClass wp : wrapperList) {
            if(wp.selected) {
                selectedRecords.add(wp.con);
            }
        }
        insert selectedRecords;
    }
    public class WrapperClass {
        public Contact con {get;set;}
        public Boolean selected {get;set;}
        public WrapperClass (Contact c) {
            con=c;
            selected=false;
        }
        public WrapperClass(){}
    }
}

//VF Page

<apex:page standardController="Account" extensions="AccountContactWrapper">
    <apex:form >
        <apex:pageBlock id="block">
            <apex:pageBlockButtons location="bottom">
                <!--<apex:commandButton value="Edit" action="{!processedRecords}"/>-->
                <apex:commandButton value="Delete Selected Records" action="{!deleteRecords}"/>
                <apex:commandButton value="Create Contact" action="{!createNewContact}"/>
                <apex:commandButton value="Save" action="{!saveRecords}"/>
            </apex:pageBlockButtons>
            <apex:pageBlockSection >
                <apex:pageBlockTable value="{!wrapperList}" var="wrap" id="table">
                    <apex:column >
                        <apex:inputCheckbox value="{!wrap.selected}"/>
                    </apex:column>
                    <apex:column headerValue="First Name">
                        <apex:inputField value="{!wrap.con.FirstName}"/>
                    </apex:column>
                    <apex:column headerValue="Last Name">
                        <apex:inputField value="{!wrap.con.LastName}"/>
                    </apex:column>
                    <apex:column headerValue="Phone">
                        <apex:inputField value="{!wrap.con.Phone}"/>
                    </apex:column>
                </apex:pageBlockTable>
            </apex:pageBlockSection>
        </apex:pageBlock>
    </apex:form>
</apex:page>