Copy a Snapshot into an Image Item with javascript scripting

Setup, Configuration and Use Scripts & Rules
1

Hello,
I want to save a snapshot to a static image. I used a DSL rule from the forum and converted it to Javascript. As a DSL rule it works perfectly.
Unfortunately it doesn’t work in JavaScript.
I’ve created several log entries so I can isolate the error, but I can’t fix it.
Can someone please give me a tip?

Here is the JavaScript:

var URL = Java.type("java.net.URL");
var RawType = Java.type("org.openhab.core.library.types.RawType");

rules.JSRule({
    name: "ab_JS Test Camera",
    description: "Test JS Camera",
    triggers: [
        triggers.ItemStateUpdateTrigger('swTestSwitch', '', 'ON')
    ],
    execute: (event) => {

        const snapURL = items['SnapShotUri_Arenti_IN1_1'].state.toString();
        console.log("snapURL: " + snapURL);

        const url = new URL(snapURL);
        const connection = url.openConnection();

        const contentType = connection.getContentType();
        console.log("copyImageLocal: " + "after contentType [ " + contentType.toString() + " ]");

        const inputStream = connection.getInputStream();
        console.log("copyImageLocal: " + "after getInputStream");

        const bytes = inputStream.readAllBytes();
        console.log("copyImageLocal: " + "after bytes");

        const image = new RawType(bytes, contentType);
        console.log("copyImageLocal: " + "after RawType");

        items['pictureLetterbox'].postUpdate(image);
    }
})

Here are the log entries:

2023-10-06 15:25:25.033 [INFO ] [hab.automation.script.file.camera.js] - snapURL: http://192.168.2.167:5000/webapi/entry.cgi?api=SYNO.SurveillanceStation.Camera&version=8&method=GetSnapshot&_sid=lKqX-mkSLdq7UBHQl0Pyz9pAsZgFD2ycSem92mXwIfIDD5qJFSsF_zn48-2Z2ZYzkJXSKQjqbc_WZ4EEUYJwg0&camStm=1&cameraId=3
2023-10-06 15:25:25.276 [INFO ] [hab.automation.script.file.camera.js] - copyImageLocal: after contentType [ image/jpeg ]
2023-10-06 15:25:25.278 [WARN ] [e.automation.internal.RuleEngineImpl] - Failed to execute action: 1(java.lang.IllegalStateException: java.lang.IllegalAccessException: access to public member failed: sun.net.www.protocol.http.HttpURLConnection.getInputStream[Ljava.lang.Object;@541d4b99/invokeVirtual, from public Lookup)
org.graalvm.polyglot.PolyglotException: java.lang.IllegalStateException: java.lang.IllegalAccessException: access to public member failed: sun.net.www.protocol.http.HttpURLConnection.getInputStream[Ljava.lang.Object;@541d4b99/invokeVirtual, from public Lookup
	at com.oracle.truffle.host.HostMethodDesc$SingleMethod$MethodMHImpl.makeMethodHandle(HostMethodDesc.java:394) ~[?:?]

Thanks in advance.