public void setSubstitutions(java.util.Map<String, java.util.List<String>> substitutions) {
        this.substitutions = substitutions;
    }
<p>
The default message variables to use in the notification message. You can override the default variables with
individual address variables.
</p>

@param substitutions
       The default message variables to use in the notification message. You can override the default variables
       with individual address variables.
aws-java-sdk-pinpoint/src/main/java/com/amazonaws/services/pinpoint/model/GCMMessage.java