getBytes not working in JavaScript and Python

[fi7z]

    var javaString = Java.type('java.lang.String');
    var myJavaString = new javaString("Hello GraalVM");
    var bytes = myJavaString.getBytes();

Throws

TypeError: test.getBytes is not a function
	at <js> main(Unnamed:3:57-71)
	at <js> :program(Unnamed:6:101-118)
	at org.graalvm.polyglot.Context.eval(Context.java:446)
	at burp_hotpatch.scripts.ScriptExecutionContainer.execute(ScriptExecutionContainer.java:86)
	at burp_hotpatch.threads.ScriptExecutionThread.run(ScriptExecutionThread.java:19)