public UserData withContacts(AgentContactReference... contacts) {
        if (this.contacts == null) {
            setContacts(new java.util.ArrayList<AgentContactReference>(contacts.length));
        }
        for (AgentContactReference ele : contacts) {
            this.contacts.add(ele);
        }
        return this;
    }
<p>
A list of contact reference information.
</p>
<p>
<b>NOTE:</b> This method appends the values to the existing list (if any). Use
{@link #setContacts(java.util.Collection)} or {@link #withContacts(java.util.Collection)} if you want to override
the existing values.
</p>

@param contacts
       A list of contact reference information.
@return Returns a reference to this object so that method calls can be chained together.
aws-java-sdk-connect/src/main/java/com/amazonaws/services/connect/model/UserData.java