ITW uses the default OpenJDK useragent string, which can be customized with the http.agent system property.
openjdk/jdk/src/share/classes/sun/net/www/protocol/http/HttpURLConnection.java

String agent = java.security.AccessController.doPrivileged(
new sun.security.action.GetPropertyAction("http.agent"));
if (agent == null) {
agent = "Java/"+version;
} else {
agent = agent + " Java/"+version;
}
userAgent = agent;
Update ITW to provide a default JNLP specific useragent string instead of the generic "Java/<version>" (e.g. Java/1.8.0_352).