Minecraft Forums

For two days now, I have been trying to install The better world generation mod (outdated) and optifine on 1.3.2. Whenever I delete META-INF, minecraft redownload my jar file anyway, even when I don't add any mods. It works in offline mode, however I am trying to play on a LAN server with a friend. I am not a noob, I have played since beta 1.8, and have downloaded a plethora of mods. Thank you.

Now it will not launch when offline:

Nov 23, 2015 8:45:29 PM net.minecraft.launchwrapper.LogWrapper log
INFO: Using tweak class name net.minecraft.launchwrapper.VanillaTweaker
Exception in thread "main" java.lang.NoClassDefFoundError: up
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2615)
at java.lang.Class.getMethod0(Class.java:2856)
at java.lang.Class.getMethod(Class.java:1668)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:54)
at net.minecraft.launchwrapper.Launch.main(Launch.java:18)
Caused by: java.lang.ClassNotFoundException: up
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:179)
at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
... 6 more
Caused by: java.lang.IncompatibleClassChangeError: Implementing class
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:800)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:171)
... 8 more

i would recommend just using multimc to install mods, i hope this helps. also if you already know about multimc, i'm sorry for not being helpful.

-meelock