public ObjectTypeKey withFieldNames(String... fieldNames) {
        if (this.fieldNames == null) {
            setFieldNames(new java.util.ArrayList<String>(fieldNames.length));
        }
        for (String ele : fieldNames) {
            this.fieldNames.add(ele);
        }
        return this;
    }
<p>
The reference for the key name of the fields map.
</p>
<p>
<b>NOTE:</b> This method appends the values to the existing list (if any). Use
{@link #setFieldNames(java.util.Collection)} or {@link #withFieldNames(java.util.Collection)} if you want to
override the existing values.
</p>

@param fieldNames
       The reference for the key name of the fields map.
@return Returns a reference to this object so that method calls can be chained together.
aws-java-sdk-customerprofiles/src/main/java/com/amazonaws/services/customerprofiles/model/ObjectTypeKey.java