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Reflection error-used Obf helper, works in eclipse, not in minecraft.


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So I found a way to work around the already-terrible attribute system using reflection and player capabilities. Using this, I was able to modify player speed quite nicely, and it worked, and using ObfuscationReflectionHelper I made it so it SHOULD work in normal minecraft. However, it does not :/.


The crash log

---- Minecraft Crash Report ----
// Ouch. That hurt 

Time: 9/25/13 7:20 PM
Description: Ticking entity

cpw.mods.fml.relauncher.ReflectionHelper$UnableToAccessFieldException: cpw.mods.fml.relauncher.ReflectionHelper$UnableToFindFieldException: java.lang.NoSuchFieldException: field_73357_f
at cpw.mods.fml.relauncher.ReflectionHelper.setPrivateValue(ReflectionHelper.java:140)
at cpw.mods.fml.common.ObfuscationReflectionHelper.setPrivateValue(ObfuscationReflectionHelper.java:104)
at rareores.Common.PlayerTickHandler.onPlayerTick(PlayerTickHandler.java:135)
at rareores.Common.PlayerTickHandler.tickStart(PlayerTickHandler.java:164)
at cpw.mods.fml.common.SingleIntervalHandler.tickStart(SingleIntervalHandler.java:28)
at cpw.mods.fml.common.FMLCommonHandler.tickStart(FMLCommonHandler.java:122)
at cpw.mods.fml.common.FMLCommonHandler.onPlayerPreTick(FMLCommonHandler.java:383)
at net.minecraft.entity.player.EntityPlayer.func_70071_h_(EntityPlayer.java:282)
at net.minecraft.client.entity.EntityClientPlayerMP.func_70071_h_(SourceFile:46)
at net.minecraft.world.World.func_72866_a(World.java:2350)
at net.minecraft.world.World.func_72870_g(World.java:2311)
at net.minecraft.world.World.func_72939_s(World.java:2157)
at net.minecraft.client.Minecraft.func_71407_l(Minecraft.java:1919)
at net.minecraft.client.Minecraft.func_71411_J(Minecraft.java:908)
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:836)
at net.minecraft.client.main.Main.main(SourceFile:101)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:131)
at net.minecraft.launchwrapper.Launch.main(Launch.java:27)
Caused by: cpw.mods.fml.relauncher.ReflectionHelper$UnableToFindFieldException: java.lang.NoSuchFieldException: field_73357_f
at cpw.mods.fml.relauncher.ReflectionHelper.findField(ReflectionHelper.java:87)
at cpw.mods.fml.relauncher.ReflectionHelper.setPrivateValue(ReflectionHelper.java:136)
... 21 more
Caused by: java.lang.NoSuchFieldException: field_73357_f
at java.lang.Class.getDeclaredField(Unknown Source)
at cpw.mods.fml.relauncher.ReflectionHelper.findField(ReflectionHelper.java:78)
... 22 more


My code

        PlayerCapabilities cap = player.capabilities;
float speed = cap.getWalkSpeed();
speed *=1.5;
ObfuscationReflectionHelper.setPrivateValue(PlayerCapabilities.class, cap, speed ,"walkSpeed","field_73357_f");


walkSpeed is a private value in playercapabilities, and I got the field_73357_f from fields.csv in /mcp/conf


Help appreciated :)



This is the creator of the Rareores mod! Be sure to check it out at

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1. When modifying speed, it modifies your players field of view, which can get annoying...

2. I've only gotten it to work in a very crude way, that glitches up, and could cause incompatibilities with other mods.


Aside from that, Can anyone help me with my issue? :l

This is the creator of the Rareores mod! Be sure to check it out at

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