Minecraft Forums

I downloaded a lot of mods but my mc crashed what does this mean? Caused by: java.lang.ClassNotFoundException: cen, please tell me.

I'd recommend posting the whole crashlog however I can inform you on what this means. It means exactly what it says, it could not find the class "cen" which could be because you are missing a coremod or the file is corrupted.

Oh here is the full report and the mods

---- Minecraft Crash Report ----
// Would you like a cupcake?

Time: 5/8/15 8:55 PM
Description: Initializing game

java.lang.NoClassDefFoundError: cen
at java.lang.Class.getDeclaredFields0(Native Method)
at java.lang.Class.privateGetDeclaredFields(Unknown Source)
at java.lang.Class.getField0(Unknown Source)
at java.lang.Class.getField(Unknown Source)
at cpw.mods.fml.client.FMLClientHandler.detectOptifine(FMLClientHandler.java:275)
at cpw.mods.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:190)
at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:480)
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:878)
at net.minecraft.client.main.Main.main(SourceFile:148)
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:135)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
Caused by: java.lang.ClassNotFoundException: cen
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:191)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 15 more
Caused by: java.lang.NullPointerException
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:182)
... 17 more


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Stacktrace:
at java.lang.Class.getDeclaredFields0(Native Method)
at java.lang.Class.privateGetDeclaredFields(Unknown Source)
at java.lang.Class.getField0(Unknown Source)
at java.lang.Class.getField(Unknown Source)
at cpw.mods.fml.client.FMLClientHandler.detectOptifine(FMLClientHandler.java:275)
at cpw.mods.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:190)
at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:480)

-- Initialization --
Details:
Stacktrace:
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:878)
at net.minecraft.client.main.Main.main(SourceFile:148)
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:135)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)

-- System Details --
Details:
Minecraft Version: 1.7.10
Operating System: Windows 7 (x86) version 6.1
Java Version: 1.7.0_21, Oracle Corporation
Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Oracle Corporation
Memory: 128407896 bytes (122 MB) / 194109440 bytes (185 MB) up to 523501568 bytes (499 MB)
JVM Flags: 6 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
AABB Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
FML:
Launched Version: 1.7.10-Forge10.13.3.1401-1710ls
LWJGL: 2.9.1
OpenGL: AMD Radeon HD 7540D GL version 4.2.11774 Compatibility Profile Context, ATI Technologies Inc.
GL Caps: Using GL 1.3 multitexturing.
Using framebuffer objects because OpenGL 3.0 is supported and separate blending is supported.
Anisotropic filtering is supported and maximum anisotropy is 16.
Shaders are available because OpenGL 2.1 is supported.

Is Modded: Definitely; Client brand changed to 'fml,forge'
Type: Client (map_client.txt)
Resource Packs: []
Current Language: ~~ERROR~~ NullPointerException: null
Profiler Position: N/A (disabled)
Vec3 Pool Size: 0 (0 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
Anisotropic Filtering: Off (1)

Treecapitator

Ars Magica

Tinkers Contruct

Lucky Block

Gravestones

eternal isles

MCA

Modular Powersuits

Thermal Expansion

Applied Energistics

Animal Bikes

That is actually very little RAM dedicated to MC, I'm not saying that's what caused the crash but it could cause other issues.

How to exactly add more RAM, i never really messed with mc settings just bought the game and played

I'm assuming you're using the vanilla launcher?