In my mod, I made an item which can teleport you into the nether.

But when I use it, I get a NullPointerException with following stack trace:

java.lang.NullPointerException: Ticking player
	at net.minecraft.world.Teleporter.placeInExistingPortal(Teleporter.java:136)
	at net.minecraft.world.Teleporter.placeInPortal(Teleporter.java:36)
	at net.minecraft.server.management.PlayerList.transferEntityToWorld(PlayerList.java:748)
	at net.minecraft.server.management.PlayerList.transferPlayerToDimension(PlayerList.java:655)
	at net.minecraft.server.management.PlayerList.changePlayerDimension(PlayerList.java:642)
	at net.minecraft.entity.player.EntityPlayerMP.changeDimension(EntityPlayerMP.java:745)
	at com.deerangle.item.ItemChocolateBar.onFoodEaten(ItemChocolateBar.java:197)
	at com.deerangle.item.ItemChocolateBar.onItemUseFinish(ItemChocolateBar.java:117)
	at net.minecraft.item.ItemStack.onItemUseFinish(ItemStack.java:242)
	at net.minecraft.entity.EntityLivingBase.onItemUseFinish(EntityLivingBase.java:3062)
	at net.minecraft.entity.player.EntityPlayerMP.onItemUseFinish(EntityPlayerMP.java:1227)
	at net.minecraft.entity.EntityLivingBase.updateActiveHand(EntityLivingBase.java:2956)
	at net.minecraft.entity.EntityLivingBase.onUpdate(EntityLivingBase.java:2311)
	at net.minecraft.entity.player.EntityPlayer.onUpdate(EntityPlayer.java:272)
	at net.minecraft.entity.player.EntityPlayerMP.onUpdateEntity(EntityPlayerMP.java:423)
	at net.minecraft.network.NetHandlerPlayServer.update(NetHandlerPlayServer.java:185)
	at net.minecraftforge.fml.common.network.handshake.NetworkDispatcher$1.update(NetworkDispatcher.java:212)
	at net.minecraft.network.NetworkManager.processReceivedPackets(NetworkManager.java:307)
	at net.minecraft.network.NetworkSystem.networkTick(NetworkSystem.java:196)
	at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:863)
	at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:741)
	at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:192)
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:590)
	at java.lang.Thread.run(Unknown Source)

 

 

Solution:

instead of 

player.changeDimension(-1);

use 

player.setPortal(player.getPosition());
player.changeDimension(-1);

 

Edited January 7, 20187 yr by deerangle
solved

private void onFoodEaten(int meta, ItemStack stack, World worldIn, EntityPlayer player) {
	if (!worldIn.isRemote) {
		player.changeDimension(-1);
	}
}

 

Okay! 

double d6 = (double)(blockpattern$patternhelper.getFrontTopLeft().getY() + 1) - entityIn.getLastPortalVec().y * (double)blockpattern$patternhelper.getHeight();

this is the line of code in the Teleporter class, that crashes the game.

since the blockpattern$patternhelper object is created 3 lines above, it must be either entityIn or entityIn.getLastPortalVec().

I assume it is actually entityIn.getLastPortalVec(). The variable returned by this function is only set in the Entity#setPortal(BlockPos pos).

1 minute ago, deerangle said:

double d6 = (double)(blockpattern$patternhelper.getFrontTopLeft().getY() + 1) - entityIn.getLastPortalVec().y * (double)blockpattern$patternhelper.getHeight();

this is the line of code in the Teleporter class, that crashes the game.

since the blockpattern$patternhelper object is created 3 lines above, it must be either entityIn or entityIn.getLastPortalVec().

I assume it is actually entityIn.getLastPortalVec(). The variable returned by this function is only set in the Entity#setPortal(BlockPos pos).

I managed to solve my problem with exactly this. Thank you for the tips, @diesieben07