sgx-lkl: StringUtils.toLowerCase will cause problem when run as jvm app

Hi guys, when I run some code as jvm app in sgx-lkl simulation mode , it will exit with no output or exception. e.g.

System.out.println("Hello World");   // will print
String lowered = StringUtils.toLowerCase("ADSAFFDSzcxcx");
System.out.println(lowered); // will not print

in jdk, it’s

public static String toLowerCase(String str) {
        return str.toLowerCase(Locale.ENGLISH);
    }

Is this related to Locale class in Alphine? And I also wander that how can I debug jvm app in sgx-lkl simulation mode?

please help here. Thanks