MessagingController.java

    public String messageBuilder(Price price, String symbol) {
        return String.format("Here are the most up-to-date %s prices:\n" +
               "\uD83C\uDF05 Open price of the day: $%s\n" +
               "\uD83D\uDCC8 High price of the day: $%s\n" +
               "\uD83D\uDCC9 Low price of the day: $%s\n" +
               "\uD83D\uDD14 Current price: $%s\n" +
               "\uD83D\uDCC6 Previous close price: $%s\n" +
               "\uD83E\uDD1E Send another symbol.",
            symbol, price.open, price.high, price.low, price.current, price.close);
    }

OMG I just learned this:
if you put <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> into the <properties> section of pom.xml you can write your code like this:

    public String messageBuilder(Price price, String symbol) {
        return String.format("Here are the most up-to-date %s prices:\n" +
               "🌅 Open price of the day: $%s\n" +
               "📈 High price of the day: $%s\n" +
               "📉 Low price of the day: $%s\n" +
               "🔔 Current price: $%s\n" +
               "📆 Previous close price: $%s\n" +
               "🤞 Send another symbol.",
            symbol, price.open, price.high, price.low, price.current, price.close);
    }

(if you're trying to copy-paste emoji into IntelliJ you might need to use ctrl-shift-v to paste without formatting, but it works)

omg this is so cool!