When I launch Minecraft, nothing happens. The launcher just dissapears. I've tried to re-install forge, and java and it still does the same thing. Unless I use forge for 1.6.4, It doesn't work. The mod I want to use cannot be downgraded to 1.6.4 though. PLEASE if anyone knows what to do, I would be very greatful. This is the error report:

 

 

[20:28:46] [main/INFO] [LaunchWrapper]: Loading tweak class name cpw.mods.fml.common.launcher.FMLTweaker

[20:28:46] [main/INFO] [LaunchWrapper]: Using primary tweak class name cpw.mods.fml.common.launcher.FMLTweaker

[20:28:46] [main/INFO] [LaunchWrapper]: Calling tweak class cpw.mods.fml.common.launcher.FMLTweaker

[20:28:46] [main/INFO] [FML]: Forge Mod Loader version 7.2.217.1147 for Minecraft 1.7.2 loading

[20:28:46] [main/INFO] [FML]: Java is Java HotSpot Client VM, version 1.8.0_20, running on Windows Vista:x86:6.0, installed at C:\Program Files\Java\jre1.8.0_20

[20:28:46] [main/INFO] [LaunchWrapper]: Loading tweak class name cpw.mods.fml.common.launcher.FMLInjectionAndSortingTweaker

[20:28:46] [main/INFO] [LaunchWrapper]: Loading tweak class name cpw.mods.fml.common.launcher.FMLDeobfTweaker

[20:28:46] [main/INFO] [LaunchWrapper]: Calling tweak class cpw.mods.fml.common.launcher.FMLInjectionAndSortingTweaker

[20:28:46] [main/ERROR] [LaunchWrapper]: Unable to launch

java.util.ConcurrentModificationException

at java.util.ArrayList$Itr.checkForComodification(Unknown Source) ~[?:1.8.0_20]

at java.util.ArrayList$Itr.remove(Unknown Source) ~[?:1.8.0_20]

at net.minecraft.launchwrapper.Launch.launch(Launch.java:117) [launchwrapper-1.9.jar:?]

at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.9.jar:?]

Java HotSpot Client VM warning: Using incremental CMS is deprecated and will likely be removed in a future release

 

 

 

Before you tell me not to use java 8, I have tried with 6 and 7.

Use latest forge.

I have tried the latest and recomended builds of both 1.7.2 and 1.7.10. Neither work, and both give the same error.