Loadrunner: Illegal reflective access...to constructor javax.swing.SwingUtilities()

Hello,

my load test doesnt run with the load test runner, but in the GUI. 

Running ReadyAPI LoadUITestRunner for [LT_ReservationFlow_BaseLine]
directory: C:\Program Files\SmartBear\ReadyAPI-3.1.0\bin\.
command: cmd.exe /C loadtestrunner.bat C:\Users\XXXXXXXX\GitRepos\NLST-EVENTFROST-TESTS-ReadyApi -nLT_ReservationFlow_BaseLine -Etst -rC:\Users\XXXXXXXX\Tmp\Testresult -FHTML -j -J
Configuring log4j from [C:\Program Files\SmartBear\ReadyAPI-3.1.0\bin\soapui-log4j.xml]
15:54:00,172 INFO  [license] ReadyAPI 3.1.0 (build 5047) started - System properties: {OS=Windows 10, User name=XXXXXXXXXX}
15:54:00,379 INFO  [DefaultSoapUICore] SoapUI settings were initialized from [C:\Users\XXXXXXXXXX\soapui-settings.xml]
15:54:00,416 INFO  [SoapUIExtensionClassLoader] "C:\Program Files\SmartBear\ReadyAPI-3.1.0\bin\ext\postgresql-9.3-1102.jdbc41.jar" has been added to the classpath.
15:54:00,417 INFO  [SoapUIExtensionClassLoader] "C:\Program Files\SmartBear\ReadyAPI-3.1.0\bin\ext\sqljdbc42.jar" has been added to the classpath.
15:54:00,418 WARN  [SoapUIExtensionClassLoader] The custom library "C:\Program Files\SmartBear\ReadyAPI-3.1.0\bin" does not exist.
15:54:00,472 INFO  [DefaultSoapUICore] 2 JDBC drivers have been registered from the directory bin/ext: [org.postgresql.Driver, com.microsoft.sqlserver.jdbc.SQLServerDriver].
15:54:00,775 WARN  [SoapUIProGroovyScriptEngineFactory] Missing scripts folder [C:\Program Files\SmartBear\ReadyAPI-3.0.0\bin\scripts]
15:54:00,778 INFO  [DefaultSoapUICore] Adding listeners from [C:\Program Files\SmartBear\ReadyAPI-3.1.0\bin\listeners\demo-listeners.xml]
15:54:00,807 WARN  [SoapUIJasperReportManager] The report directory "C:\Program Files\SmartBear\ReadyAPI-3.1.0\bin" does not exist. The default report directory will be used.
15:54:08,686 INFO  [PluginManager] 5 plugins loaded in 942 ms
15:54:08,687 INFO  [DefaultSoapUICore] All plugins loaded
15:54:08,808 WARN  [SoapUIProGroovyScriptEngineFactory] Missing scripts folder [C:\Program Files\SmartBear\ReadyAPI-3.0.0\bin\scripts]
15:54:08,970 INFO  [BaseExecutionManager] Initialized base directory to keep executions to C:\Users\XXXXXXXXXXX\.readyapi\loadui\results
Configuring log4j from [C:\Program Files\SmartBear\ReadyAPI-3.1.0\bin\soapui-log4j.xml]
15:54:09,389 INFO  [license] ReadyAPI 3.1.0 (build 5047) started - System properties: {OS=Windows 10, User name=XXXXXXXXXXX}
15:54:09,401 INFO  [DefaultSoapUICore] SoapUI settings were initialized from [C:\Users\XXXXXXXXXX\soapui-settings.xml]
15:54:09,405 INFO  [SoapUIExtensionClassLoader] "C:\Program Files\SmartBear\ReadyAPI-3.1.0\bin\ext\postgresql-9.3-1102.jdbc41.jar" has been added to the classpath.
15:54:09,405 INFO  [SoapUIExtensionClassLoader] "C:\Program Files\SmartBear\ReadyAPI-3.1.0\bin\ext\sqljdbc42.jar" has been added to the classpath.
15:54:09,406 WARN  [SoapUIExtensionClassLoader] The custom library "C:\Program Files\SmartBear\ReadyAPI-3.1.0\bin" does not exist.
15:54:09,462 INFO  [DefaultSoapUICore] 2 JDBC drivers have been registered from the directory bin/ext: [org.postgresql.Driver, com.microsoft.sqlserver.jdbc.SQLServerDriver].
15:54:09,463 INFO  [DefaultSoapUICore] Adding listeners from [C:\Program Files\SmartBear\ReadyAPI-3.1.0\bin\listeners\demo-listeners.xml]
15:54:12,223 INFO  [PluginManager] 5 plugins loaded in 607 ms
15:54:12,223 INFO  [DefaultSoapUICore] All plugins loaded
15:54:12,248 DEBUG [LicenseManagerServiceImpl] Trying to initialize license for ReadyAPI Bundle
15:54:12,249 DEBUG [LicenseManagerServiceImpl] License host for ReadyAPI Bundle: NB102213
15:54:12,270 DEBUG [LicenseManagerServiceImpl] Valid license file found: C:\Users\XXXXXXXXXX\.readyapi\readyapibundle.key, last modified: 2019-09-13T09:50:53.146+0200
Running LoadUI Project Runner... Project: C:\Users\XXXXXXXXXX\GitRepos\NLST-EVENTFROST-TESTS-ReadyApi
15:54:12,908 WARN  [CompositeProjects] The file has not been loaded, because it is not specified in the project: C:\Users\XXXXXXXXXX\GitRepos\NLST-EVENTFROST-TESTS-ReadyApi\TS_Rerservation\TC_ReservationFlow4LTBatch.xml
15:54:12,909 WARN  [CompositeProjects] The file has not been loaded, because it is not specified in the project: C:\Users\XXXXXXXXXX\GitRepos\NLST-EVENTFROST-TESTS-ReadyApi\TS_Rerservation\TC_ReservationFlowWithDelay4LT.xml
15:54:13,368 INFO  [WsdlProject] Loaded project from [file:/C:/Users/XXXXXXXXXX/GitRepos/NLST-EVENTFROST-TESTS-ReadyApi/]
15:54:14,097 WARN  [SoapUIProGroovyScriptEngineFactory] Missing scripts folder [C:\Program Files\SmartBear\ReadyAPI-3.0.0\bin\scripts]

-----------------------------------------
STARTING LOADUI COMMAND LINE RUNNER 
-----------------------------------------

-----------------------------------------
RUNNING TEST: LT_ReservationFlow_BaseLine
LIMITS: Time: 00:20:00 Targets: N/A Failures: N/A
-----------------------------------------
Time: 00:00:00 VUs: 0 TPS: 0 Targets: 0 Failures: 0
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.codehaus.groovy.reflection.CachedConstructor$1 (file:/C:/Program%20Files/SmartBear/ReadyAPI-3.1.0/lib/groovy-all-2.4.17.jar) to constructor javax.swing.SwingUtilities()
WARNING: Please consider reporting this to the maintainers of org.codehaus.groovy.reflection.CachedConstructor$1
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
Time: 00:00:01 VUs: 5 TPS: 32 Targets: 5 Failures: 5
15:59:17,152 INFO  [CanvasItemImpl] Generating a summary report for CanvasItem LT_ReservationFlow_BaseLine.
-----------------------------------------
TEST EXECUTION COMPLETED
FINAL RESULTS: Time: 00:00:01  Targets: 5 Failures: 5
-----------------------------------------
15:59:23,569 INFO  [license] ReadyAPI 3.1.0 shutting down

Does anyone know what it is?