Calling java class from mock script

Hi,

I have a mock soap service and want to  do some magic with basic auth headers. When I try to import the java.utils.Base64 I get class not found errrors. Are the std java classes not on the classpath? 

Searching for this problem only gives examples of custom classes.  The documentation and API suggest only a limited set of XML/SOAP/JSON/REST classes.

Thnx,

Wim-Jan

Adding relevant piece of groovy:

note that it is to help clarify the issue and  imcomplete since I cut out or substituted sensitive info

import java.utils.Base64

def groovyUtils = new com.eviware.soapui.support.GroovyUtils(context)
def alert = com.eviware.soapui.support.UISupport;

log.info("------------- begin call -----------------------------");

def soapRequest = mockRequest.requestContent;
def headers = mockRequest.requestHeaders;
def incommingBasicAuth = headers.get("Authorization", "defaultAuth");
if (incommingBasicAuth == "defaultAuth") {
	log.info("no basicAuth header found!");
} else {
	String decodedAuth = Base64.getDecoder().decode;
	def uNamePw = decodedAuth.split(":");
  
	log.info("basicAuth header for " + uNamePw + " found!");
}

log.info("--- request will be forwarded to actual service ----")
  
String basicAuth = "";

if (incommingBasicAuth == "defaultAuth") {
	log.info("Set hardcoded username,password");
	String userCredentials = "someuser:somepw";
	basicAuth = "Basic " + new String(Base64.getEncoder().encode(userCredentials.getBytes()));
} else {
	log.info("use username password form incomming request");
	basicAuth = incommingBasicAuth;
}

def soapUrl = new URL("https://somewebservice.nl/")
def connection = soapUrl.openConnection()

// insert the basic auth header
connection.setRequestProperty("Authorization", basicAuth);

connection.setRequestMethod("POST")
connection.setRequestProperty("Content-Type", "text/html")
connection.setRequestProperty("SOAPAction", "")
connection.doOutput = true

Writer writer = new OutputStreamWriter(connection.outputStream);
writer.write(soapRequest)
writer.flush()
writer.close()
connection.connect()


def soapResponse = connection.content.text

// work as proxy, i.e. just return response recieved from https://somewebservice.nl/
requestContext.responseMessage = soapResponse