I really don't know how to put this, so I'll just tell you my scenario.

I was doing some recipe editing for my mod, and I accidentally tried to run the code when an instance was already running. After shutting both down, I ran it again and it stopped short. There was no crash to what I could see, It just ran for a very small amount of time then stopped.

Here's what I'm seeing in the console:

 

 

Oct 26, 2014 6:44:03 PM net.minecraft.launchwrapper.LogWrapper log

INFO: Loading tweak class name cpw.mods.fml.common.launcher.FMLTweaker

Oct 26, 2014 6:44:03 PM net.minecraft.launchwrapper.LogWrapper log

SEVERE: Unable to launch

java.lang.ClassNotFoundException: cpw.mods.fml.common.launcher.FMLTweaker

at java.net.URLClassLoader$1.run(Unknown Source)

at java.net.URLClassLoader$1.run(Unknown Source)

at java.security.AccessController.doPrivileged(Native Method)

at java.net.URLClassLoader.findClass(Unknown Source)

at java.lang.ClassLoader.loadClass(Unknown Source)

at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)

at java.lang.ClassLoader.loadClass(Unknown Source)

at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:102)

at java.lang.ClassLoader.loadClass(Unknown Source)

at java.lang.ClassLoader.loadClass(Unknown Source)

at java.lang.Class.forName0(Native Method)

at java.lang.Class.forName(Unknown Source)

at net.minecraft.launchwrapper.Launch.launch(Launch.java:94)

at net.minecraft.launchwrapper.Launch.main(Launch.java:27)

 

Java HotSpot 64-Bit Server VM warning: Using incremental CMS is deprecated and will likely be removed in a future release

 

 

I have no idea what this is and how to fix it. Any help would be appreciated.

 

Edit: I guess some of you might tell me to downgrade my Java (1.8.0_11, by the way) But it's been working fine with that version. If that is the only way, I'll do it, I'd just rather not.

Try re-setting up your workspace?

Not to sure exactly what you meant, but I re-installed Eclipse. It seemed, however, that the user preferences remained, so I assumed there was something in the forge stuff that saved Eclipse preferences. moved a folder called .metadata out of the folder in

C:\Users\MyUser\Desktop\MC Modding - 1.6.4\forge\mcp\eclipse

(the eclipse folder is where I'm running my workspace, btw) and ran it again. This time, the user preferences were gone, and a new .metadata folder was made in the right location, however, my source folder was not showing up.

I'm just going to back up all my mod stuff and re-download forge (using 1.6.4 version)

 

Edit: I went ahead and reinstalled forge and eclipse.. and it worked