Groovy script using wslite library in task listener on Apache Tomcat distribution

I have a groovy inline script inside a Task Listener that is used to call a REST endpoint, which passes the taskId and formKey and a few other data points to said endpoint.

The script uses the wslite.RESTclient class (
It works when executed locally using a Spring Boot setup, I have added the groovy-all and wslite dependencies in the pom.xml for my local spring boot installation.

Script for reference:

@Grab(group=‘org.codehaus.groovy.modules.http-builder’, module=‘http-builder’, version=‘0.7’ )


def taskNames = task.getVariable('taskName')
def taskURLs = task.getVariable('taskURL')
def userIds = task.getVariable('varAssignedUser')
def requestItems = task.getVariable('folio')

RESTClient client = new RESTClient("${portalInstance}")
def path = "endpoint/url"
def response

try {
    response = path)
        type "ContentType.json"
        json taskName:taskNames, taskURL:taskURLs, userID:userIds, requestItem:requestItems

} catch (RESTClientException e) {
    return 500

However, when I try to execute the process on an Apache Tomcat installation on an ec2 instance, the task fails and closes the process. If the task is in the first executions, the process will not be initiated properly.

I have tried to add:


To the apache-tomcat.x.x.x/lib/ folder.
According to the documentation simply putting the jar files in the folder should be enough, is that correct?
Or do I need to specify the wslite classes somewhere in the configuration file in /conf/bpm-platform.xml?

After much troubleshooting I was able to identify and solve the issue on my own!

The solution was to remove the @Grab (1st line) part of the script. However, I’m not sure why this worked fine on a local spring boot install but not on Apache Tomcat dedicated server.

Either way this did the trick and the rest call works perfectly and passes all variables without issue.
Now I’m trying to find a more elegant way to do this, like an intermediate event.