public java.util.List<GameProperty> getGameProperties() {
        return gameProperties;
    }
<p>
A set of key-value pairs that can store custom data in a game session. For example:
<code>{"Key": "difficulty", "Value": "novice"}</code>. This information is added to the new
<code>GameSession</code> object that is created for a successful match. This parameter is not used if
<code>FlexMatchMode</code> is set to <code>STANDALONE</code>.
</p>

@return A set of key-value pairs that can store custom data in a game session. For example:
        <code>{"Key": "difficulty", "Value": "novice"}</code>. This information is added to the new
        <code>GameSession</code> object that is created for a successful match. This parameter is not used if
        <code>FlexMatchMode</code> is set to <code>STANDALONE</code>.
aws-java-sdk-gamelift/src/main/java/com/amazonaws/services/gamelift/model/UpdateMatchmakingConfigurationRequest.java