I am trying to use another class to hold the code that adds objects to the dataWatcher of an entity, but when I try to call the function in the other class in the entityInit() function in my entity, I get this error:

 

 

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: java.lang.reflect.InvocationTargetException

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at java.lang.reflect.Constructor.newInstance(Unknown Source)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at net.minecraft.entity.EntityList.createEntityByID(EntityList.java:221)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at net.minecraft.item.ItemMonsterPlacer.spawnCreature(ItemMonsterPlacer.java:173)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at net.minecraft.item.ItemMonsterPlacer.onItemUse(ItemMonsterPlacer.java:79)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at net.minecraftforge.common.ForgeHooks.onPlaceItemIntoWorld(ForgeHooks.java:507)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at net.minecraft.item.ItemStack.tryPlaceItemIntoWorld(ItemStack.java:142)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at net.minecraft.server.management.ItemInWorldManager.activateBlockOrUseItem(ItemInWorldManager.java:422)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at net.minecraft.network.NetHandlerPlayServer.processPlayerBlockPlacement(NetHandlerPlayServer.java:593)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at net.minecraft.network.play.client.C08PacketPlayerBlockPlacement.processPacket(C08PacketPlayerBlockPlacement.java:74)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at net.minecraft.network.play.client.C08PacketPlayerBlockPlacement.processPacket(C08PacketPlayerBlockPlacement.java:122)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at net.minecraft.network.NetworkManager.processReceivedPackets(NetworkManager.java:241)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at net.minecraft.network.NetworkSystem.networkTick(NetworkSystem.java:182)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:726)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:614)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:118)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:485)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at net.minecraft.server.MinecraftServer$2.run(MinecraftServer.java:752)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: Caused by: java.lang.NullPointerException

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at ashjack.evolve.entity.EvolvingEntity.entityInit(EvolvingEntity.java:55)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at net.minecraft.entity.Entity.<init>(Entity.java:220)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at net.minecraft.entity.EntityLivingBase.<init>(EntityLivingBase.java:155)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at net.minecraft.entity.EntityLiving.<init>(EntityLiving.java:78)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at net.minecraft.entity.EntityCreature.<init>(EntityCreature.java:36)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at net.minecraft.entity.EntityAgeable.<init>(EntityAgeable.java:17)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at net.minecraft.entity.passive.EntityAnimal.<init>(EntityAnimal.java:34)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at ashjack.evolve.entity.EntityAnimalMob.<init>(EntityAnimalMob.java:22)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: at ashjack.evolve.entity.EvolvingEntity.<init>(EvolvingEntity.java:38)

[20:34:56] [server thread/INFO] [sTDERR]: [java.lang.Throwable$WrappedPrintStream:println:-1]: ... 20 more

 

 

Here is my code:

 

MyEntity.java

public DataWatcher dataWatcher = this.dataWatcher;
public List<Gene> entityGenes = new ArrayList<Gene>();
public void entityInit()
    {
	for(int i=0; i<entityGenes.size(); i++) //<---The error point to this line of code
	{
		entityGenes.get(i).entityInit();
	}

	/*this.dataWatcher.addObject(16, Byte.valueOf((byte) - 1));
	this.dataWatcher.addObject(17, Byte.valueOf((byte)0));               <---Adding the objects like this is fine
	this.dataWatcher.addObject(18, Byte.valueOf((byte)0));*/
        super.entityInit();
    }

 

GeneExplosive.java

public class GeneExplosive extends Gene
{
        public void entityInit()
{
                owner.dataWatcher.addObject(16, Byte.valueOf((byte) - 1));
                owner.dataWatcher.addObject(17, Byte.valueOf((byte)0));
                owner.dataWatcher.addObject(18, Byte.valueOf((byte)0));
	super.entityInit();
}
}

 

Gene.java

public abstract class Gene 
{
       public void entityInit()
{

}
}

Hi

 

5 minutes tracing with your debugger would show you this very clearly.. do you know how to use it? 

 

If you don't, I recommend you spend a couple of hours learning how to use it, it's awesome and you'll wonder how on earth you ever managed without it

eg

http://www.vogella.com/tutorials/EclipseDebugging/article.html

 

-TGG

Side note, don't use Byte.valueOf.