public void setFieldNames(java.util.Collection<String> fieldNames) {
        if (fieldNames == null) {
            this.fieldNames = null;
            return;
        }

        this.fieldNames = new java.util.ArrayList<String>(fieldNames);
    }
<p>
The reference for the key name of the fields map.
</p>

@param fieldNames
       The reference for the key name of the fields map.
aws-java-sdk-customerprofiles/src/main/java/com/amazonaws/services/customerprofiles/model/ObjectTypeKey.java