Q:

Command not doing anything

I'm trying to make a command that would send a message to the sender, but it isn't working.
Here's the main class:
public void onEnabled() {
getLogger().info("Enabled!");
}

public boolean onCommand(Command cmd, CommandSender sender, String label, String[] args) {
    if (cmd.getName().equalsIgnoreCase("hi")) {
        sender.sendMessage("Hey there " + sender);
    }
    return false;
}

A:

I don't know your plugin.yml but if it is right then it should work if you change from:
onCommand(Command cmd, CommandSender sender, String label, String[] args)

To:
onCommand(CommandSender sender, Command cmd, String label, String[] args)

And yes, order matters in onCommand() method.
To show the sender's name you need to change from:
sender.sendMessage("Hey there " + sender);

To:
sender.sendMessage("Hey there " + sender.getName());

