You need an import first. While not exactly what you are looking for, it should get you on the right track.
var Actions = Java.type("org.openhab.core.model.script.actions.Things");
var recordAction = Actions.getActions("ipcamera", "ipcamera:hikvision:FrontDoorCam").recordGIF("ipcamera",6);
var Actions = Java.type("org.openhab.core.model.script.actions.Things");
var mqttActions = Actions.getActions("mqtt","mqtt:broker:MQTT");
mqttActions.publishMQTT("zigbee2mqtt/078/set","{\"color\":{\"r\":0,\"g\":200,\"b\":0}}");
thanks for the quick feedback to everyone involved