gistfile1.java

    public void rainbowize(CommandSender sender, String[] args){
        String colorMessage = "";
        String fullMessage = "";
        for(String y : args){
            colorMessage = appendColors(y);
            fullMessage+=colorMessage+" ";
        }
        Player player = (Player) sender;
        player.chat(fullMessage);
    }

    private String appendColors(String y) {
        StringBuilder sb = new StringBuilder(y);
        for(int x = 0; x < y.length()*3; x+=3){
            sb.insert(x, getRandomColor());
        }
      return sb.toString();
    }
    
    private ChatColor getRandomColor(){
        Random rdm = new Random();
        int zz = rdm.nextInt(16);
        ChatColor randomColor = ChatColor.getByCode(zz);
        return randomColor;
    }
}