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If you create a new entity, you may have stumbled across the Attribute System, for example if you want a custom max. health value. Now a detailed explanation on what the Attribute System actually is can be found here: http://minecraft.gamepedia.com/Attribute Here I will show you how to create your own Attributes for your entity and modify all of them in code. NOTE: all attribute classes mentioned in this tutorial can be found in the package net.minecraft.entity.ai.attributes. Create a new Attribute Step 1: To create a new attribute, you first need to create a new IAttribute instance (preferably static final in your entity registry class or somewhere). Now you don't need to make a new class which implements that interface! Minecraft provides us with a standard class currently used for all its own Attributes called RangedAttribute. The constructor of that has the following parameters: IAttribute parentIn - a parent attribute if available, can be null String unlocalizedNameIn - the unlocalized name of the attribute. You can't add an attribute with the same name to an entity, so I usually precede the name with my Mod ID separated with a dot like TurretMod.MOD_ID + ".maxAmmoCapacity" double defaultValue - the default value of the attribute. This value is set as base value when the entity is first created. It can't be lower than the minimum nor higher than the maximum value or else it will throw an IllegalArgumentException double minimumValueIn - the minimum value of the attribute. This value is usually 0.0D. If the entity's attribute value falls below that, this value is used for it instead. It can't be bigger than the maximum value or else it will throw an IllegalArgumentException double maximumValueIn - the maximum value of the attribute. This value is usually Double.MAX_VALUE. If the entity's attribute value falls above that, this value is used for it instead. It can't be smaller than the minimum value or else it will throw an IllegalArgumentException Now at the end, my IAttribute instance variable looks like this: public static final IAttribute MAX_AMMO_CAPACITY = new RangedAttribute(null, TurretMod.MOD_ID + ".maxAmmoCapacity", 256.0D, 0.0D, Double.MAX_VALUE); But wait! If you want to share the attribute value and modifiers with the client, you'll need to call setShouldWatch(true) on that variable. The same way you can disable it, for whatever reason, with false instead of true as the parameter value. Conveniently it returns itself, so you can make a neat one-liner like this: public static final IAttribute MAX_AMMO_CAPACITY = new RangedAttribute(null, TurretMod.MOD_ID + ".maxAmmoCapacity", 256.0D, 0.0D, Double.MAX_VALUE).setShouldWatch(true); Step 2: Great, now you have this useless variable the entity doesn't know about. To make it useful and working with the entity, you first need to register it to the entity's attribute list. To do so, override applyEntityAttributes()(if you've not already done so while changing the entity's max. health) and call this.getAttributeMap().registerAttribute(MY_OWN_ATTRIBUTE_VARIABLE), where MY_OWN_ATTRIBUTE_VARIABLE is firstly an overly long name, but more importantly your variable of your attribute instance created in Step 1. Here's an example from my mod: @Override protected void applyEntityAttributes() { super.applyEntityAttributes(); // Make sure to ALWAYS call the super method, or else max. health and other attributes from Minecraft aren't registered!!! this.getAttributeMap().registerAttribute(TurretAttributes.MAX_AMMO_CAPACITY); } Step 3: The attribute is now instanciated and registered, but how do I use its value? Simple! Just call this.getEntityAttribute(MY_OWN_ATTRIBUTE_VARIABLE).getAttributeValue(). It returns a double. If you want it to be an int, just use the MathHelper from Minecraft, for example MathHelper.ceiling_double_int(doubleVal) Modify an Attribute Now, to modify an attribute, there are 2 ways of doing so: 1. modify its base value This is simple and straight forward, and as mentioned 2 times here so far, you may have already done this via the entity's max. health attribute. But to be complete, here's how you change the base value of an attribute with the example on the max. health: this.getEntityAttribute(SharedMonsterAttributes.maxHealth).setBaseValue(40.0D); //sets the entity max. health to 40 HP (20 hearts) Please note: this does NOT get synched with the client! If you need to edit the base value, make sure you use packets if you want it to be shared (or change it on both sides). Otherwise use modifiers! 2. add modifiers to the attribute This is a "reversable" way of changing the attribute value w/o messing with the base value. What we will do here is essentally this: http://minecraft.gamepedia.com/Attribute#Modifiers That said, much like the Attribute Instance, we need to create our own AttributeModifier instance variable. Conveniently, there is already a class for us to use called AttributeModifier. It's constructor parameters are as follows: UUID idIn - the UUID of this modifier, much like the Attribute name, this needs to be unique per Attribute. I usually give it a pre-defined, hardcoded Ver. 4 UUID via UUID.fromString("MY-UUID"), which was generated on this site. Mine looks like this: UUID.fromString("e6107045-134f-4c54-a645-75c3ae5c7a27") String nameIn - the Modifier name, can be anything except empty, preferably readable and unique for the Attribute. Since the "uniqueness" of the modifier is already defined in the UUID, you can have duplicate names. double amountIn - the Modifier value, can be anything. Note that the attribute, as prevously explained, has a min/max value and it can't get past that! int operationIn - the Operation of the Modifier (careful, magic numbers over here!). Have a direct quote from the Minecraft Wiki: Brief explanation: Operation number is the value you feed the parameter. I also made an enum for it complete with javadoc for you to copy (with credits of course) if you want: https://github.com/SanAndreasP/SAPManagerPack/blob/master/java/de/sanandrew/core/manpack/util/EnumAttrModifierOperation.java Now I've covered the parameters, it's time to make a new instance like this: MY_CUSTOM_MODIFIER = new AttributeModifier(UUID.fromString("e6107045-134f-4c54-a645-75c3ae5c7a27"), "myCustomModifier420BlazeIt", 0.360D, EnumAttrModifierOperation.ADD_PERC_VAL_TO_SUM.ordinal()); You have the new modifier instance, but what do do with it? You can add or remove modifiers from an attribute like this (method names are self-explanatory): entity.getEntityAttribute(MY_ATTRIBUTE_INSTANCE).applyModifier(MY_CUSTOM_MODIFIER); entity.getEntityAttribute(MY_ATTRIBUTE_INSTANCE).removeModifier(MY_CUSTOM_MODIFIER); Alright, you know now everything there is to know about attributes... wait, there's one more thing: attributes are saved and loaded automatically by the entity, no need to do that manually! Just make sure the client knows about the Attribute (register it properly as I've shown).

If you already understand Java (and it's painfully obvious that you don't), you would know exactly what you need to replace null with. This forum is for help with Minecraft and Forge, what you are asking for help with is Java, which is neither of the above. So before you keep whining about how nobody will help you, realize that you're in the wrong place. As is stated on this forum all the time, this is not a forum for teaching Java because you should already have a reasonable understanding of Java before you start trying to make mods. You'll find that everyone on here is perfectly helpful, you're just not listening to us.

You need to handle the random chance and random amounts yourself: generate a random number for the amount of soil and add a stack of that much soil to the list (or that many stacks of 1 soil), then generate a random number for the rock drop chance and add a rock to the drops list if it's within the 10% range.

If the isAiming() method causes an NPE, that means it's being called on a null object - so the capability must be null there. I'm not sure why that would be though. Try adding a check with hasCapability, so the method is only called if the capability is definitely present. Does the exception happen as soon as you start a world? Possibly the first player tick happens before capabilities are attached (I'm not sure), so it may just need to skip the first tick or few until the capability is present. If the capability is still null once the world is properly started, there must be some other issue with it.

It won't be the capability that's null, it's probably getMinecraft() or player. Step through with the debugger or use printlns if you want to find out for sure. But you don't really need to, because you don't need to be using that code at all - event#player won't be null.

That's because you're using ItemBlock. The base ItemBlock class doesn't give a shit about metadata. You want ItemMultiTexture or create your own (look at ItemCloth as an example).

(Welcome!) You can use the PlayerEvent.BreakSpeed event to adjust the time taken to break a block. Also, you might be better off using HarvestDropsEvent to edit the drops from a block based on the harvesting tool. That way you don't have to cancel and re-do the block break itself, you can just alter the items being dropped.

Basically this: https://github.com/Draco18s/ReasonableRealism/blob/master/src/main/java/com/draco18s/hardlib/client/ClientEasyRegistry.java#L45-L54 You need to know all the valid states the block can be in (as an item) and then register an item variant model for it: https://github.com/Draco18s/ReasonableRealism/blob/master/src/main/java/com/draco18s/hardlib/client/ClientEasyRegistry.java#L161-L168 Be aware that that class is effectively a ClientProxy class and I did stuff the way I did so that I had main class syntax similar to 1.7's GameRegistry.RegisterBlock(...) (And it was written before the registry events were added) The important bits are to determine the variant string for the blockstate variant and register an item model (the usual way) with that string.