appendable.append(";");
 	           ^^^^^^
The method append(JvmType) in the type ITreeAppendable is not applicable for the arguments (String)
...
.collect(Collectors.joining(", ")));
	                    ^^^^^^^
The method joining(CharSequence) in the type Collectors is not applicable for the arguments (String)

	public static void main(String[] args) {
		List<String> words = List.of("foo", "bar");
		CharSequence delimiter = ", ";
		String allWords = words.stream().collect(Collectors.joining(delimiter));
		System.out.println("result: " + allWords);
	}

[ERROR]         CharSequence delimiter = ", ";
[ERROR]                                  ^^^^
[ERROR] Type mismatch: cannot convert from String to CharSequence

<deriveReleaseCompilerArgumentFromTargetLevel>false</deriveReleaseCompilerArgumentFromTargetLevel>