Add reactions to JDA messages with letters

letters.java

package emoji;

import net.dv8tion.jda.core.entities.Message;

public class letters {
    
    private final String[] letters = new String[] { "\uD83C\uDDE6", "\uD83C\uDDE7", "\uD83C\uDDE8", "\uD83C\uDDE9", "\uD83C\uDDEA", "\uD83C\uDDEB", "\uD83C\uDDEC", "\uD83C\uDDED", "\uD83C\uDDEE", "\uD83C\uDDEF", "\uD83C\uDDF0", "\uD83C\uDDF1", "\uD83C\uDDF2", "\uD83C\uDDF3", "\uD83C\uDDF4", "\uD83C\uDDF5", "\uD83C\uDDF6", "\uD83C\uDDF7", "\uD83C\uDDF8", "\uD83C\uDDF9", "\uD83C\uDDFA", "\uD83C\uDDFB", "\uD83C\uDDFC", "\uD83C\uDDFD", "\uD83C\uDDFE", "\uD83C\uDDFF" };

    public void react(Message message, String reaction) {
        for (final char c : reaction.toUpperCase().toCharArray()) {
            message.addReaction(this.letters[c - 64 - 1]).queue(); // 64 is char padding, 1 is array starting at 0
        }
    }

}

Documentation? Maybe explaining what is this supposed to do?

If you happen to know Java, JDA and Discord it's simple.
This is a function that convert a string into discord letter emojis, then add them to a message as reactions

react(e.getMessage(), "TOP");