/help <pluginname> works, actual command returns nothing. Minecraft 1.14.4 plugin

I'm trying to code a minecraft plugin in 1.14.4, and /help firstplugin works, but /hello doesn't send any message.

My Main.Java:

package com.Epic_Waffle.firstplugin;

import org.bukkit.command.CommandSender;
import org.bukkit.entity.Player;
import org.bukkit.plugin.java.JavaPlugin;

import com.mojang.brigadier.Command;

import net.md_5.bungee.api.ChatColor;

public class Main extends JavaPlugin{
	
	@Override
	public void onEnable() {
		System.out.println("FirstPlugin successfully enabled!");
	}
	
	@Override
	public void onDisable() {
		System.out.println("FirstPlugin disabled with no errors!");
	}
	
	public boolean onCommand(CommandSender sender, Command cmd, String label, String[] args) {
		System.out.print(cmd);
		if(cmd.toString().equals("/hello")) {
			if(sender instanceof Player) {
				Player player = (Player) sender;
				
				player.sendMessage(ChatColor.YELLOW + "Hello!" + ChatColor.GREEN + player.getName() + ChatColor.YELLOW + "Your health has been restored!");
				player.setHealth(20.0);
				
				
			} else {
				System.out.println("You cannot use this command through console.");
			}
		}
		
		return false;
	}
	
}

My plugin.yml

version: 1.0
name: FirstPlugin
main: com.Epic_Waffle.firstplugin.Main
author: Epic_Waffle
description: FirstPlugin
commands:
  hello:
    aliases: []
    description: Cool hello command!

You have to register each command by using the Spigot API before it will be called (see the onEnable method below). You already performed the first step by adding the command to plugin.yml. I also included the documentation for this method call below. Even though these are the docs of 1.16, no changes have been made with regards to registering a CommandExecutor since 1.14. Make sure the object that you try to register implements CommandExecutor.

public void setExecutor​(@Nullable
CommandExecutor executor)
Sets the CommandExecutor to run when parsing this command
Parameters:
executor - New executor to run

Source for the documentation above.

@Override
public void onEnable() {
this.getCommand("hello").setExecutor( this );
System.out.println("FirstPlugin successfully enabled!");
}

Additionally I suggest using Command#getName() instead of toString() in your onCommand method as stated in my comment.