enum cropType {
    	//wheat, potato, carrot, beetroot, netherwart;
    	WHEAT(Material.WHEAT, Material.SEEDS),
    	POTATO(Material.POTATO_ITEM, null),
    	CARROT(Material.CARROT_ITEM, null),
    	BEETROOT(Material.BEETROOT, Material.BEETROOT_SEEDS),
    	NETHERWART(Material.NETHER_WARTS, null);

    	private final Material drops;
    	private final Material seeds;
    	private cropType(Material drops, Material seeds) {
    		this.drops = drops;
    		this.seeds = seeds;
    	}

    	public Material getDrops() {
			return drops;
    	}
    	public Material getSeeds() {
    		return seeds;
    	}


    }
    @EventHandler
    public void onBlockBreak(BlockBreakEvent e) {
        Player p = (Player) e.getPlayer();
        Block b = (Block) e.getBlock();
        ItemStack i = p.getInventory().getItemInMainHand();
        Tools tools = new Tools();

		cropType crops = null;

        if (tools.isValidCrop(b)){ //checks if block is a grown crop
        	e.getBlock().getWorld().getBlockAt(e.getBlock().getLocation()).setType(Material.AIR); //removes block



        	if (b.getType() == Material.CROPS) { //sets enum
        		crops = cropType.WHEAT;
        	} else if (b.getType() == Material.POTATO) {
        		crops = cropType.POTATO;
        	} else if (b.getType() == Material.CARROT) {
        		crops = cropType.CARROT;
        	} else if (b.getType() == Material.BEETROOT_BLOCK) {
        		crops = cropType.BEETROOT;
        	} else if (b.getType() == Material.NETHER_WARTS) {
        		crops = cropType.NETHERWART;
        	}
        	ItemStack d = new ItemStack(crops.getDrops(), tools.getDropAmount(i));
        	e.getBlock().getWorld().dropItemNaturally(e.getBlock().getLocation(), d);//drops crop
        	d = new ItemStack(crops.getSeeds(), tools.getDropAmount(i));
        	e.getBlock().getWorld().dropItemNaturally(e.getBlock().getLocation(), d);//drops seeds


[15:05:42 ERROR]: Could not pass event BlockBreakEvent to CoderTrial v1
org.bukkit.event.EventException
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:306) ~[Spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[Spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:502) [Spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:487) [Spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at net.minecraft.server.v1_11_R1.PlayerInteractManager.breakBlock(PlayerInteractManager.java:291) [Spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at net.minecraft.server.v1_11_R1.PlayerInteractManager.a(PlayerInteractManager.java:124) [Spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at net.minecraft.server.v1_11_R1.PlayerConnection.a(PlayerConnection.java:837) [Spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at net.minecraft.server.v1_11_R1.PacketPlayInBlockDig.a(SourceFile:40) [Spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at net.minecraft.server.v1_11_R1.PacketPlayInBlockDig.a(SourceFile:10) [Spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at net.minecraft.server.v1_11_R1.PlayerConnectionUtils$1.run(SourceFile:13) [Spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [?:1.8.0_131]
        at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.8.0_131]
        at net.minecraft.server.v1_11_R1.SystemUtils.a(SourceFile:46) [Spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at net.minecraft.server.v1_11_R1.MinecraftServer.D(MinecraftServer.java:747) [Spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at net.minecraft.server.v1_11_R1.DedicatedServer.D(DedicatedServer.java:399) [Spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at net.minecraft.server.v1_11_R1.MinecraftServer.C(MinecraftServer.java:678) [Spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at net.minecraft.server.v1_11_R1.MinecraftServer.run(MinecraftServer.java:576) [Spigot.jar:git-Spigot-3fb9445-6e3cec8]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_131]
Caused by: java.lang.NullPointerException
        at coderTrial.CoderTrial.onBlockBreak(CoderTrial.java:81) ~[?:?]
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_131]
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_131]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_131]
        at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_131]
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:302) ~[Spigot.jar:git-Spigot-3fb9445-6e3cec8]