public class StringUtil {
@NotNull
public static String toUpperCase(@NotNull String str) {
return str.toUpperCase();
}
}
public class Main {
public static void main(String[] args) {
String str = null;
try {
StringUtil.toUpperCase(str);
} catch (IllegalArgumentException e) {
System.out.println("IllegalArgumentException: " + e.getMessage());
}
}
}
