ShadowCraft

I'm following a minecraft 1.7 how to make a mod tutorial and I got to the part when i'm now in eclipse. Everything seemed fine, the minecaft folder was in there and there was no signs of errors on the files but when I tried to run it to see if it was ok. It wouldn't load up minecraft and it gave me this error. [09:59:15] [main/INFO] [GradleStart]: No arguments specified, assuming client. [09:59:15] [main/INFO] [GradleStart]: Extra: [] [09:59:15] [main/INFO] [GradleStart]: Running with arguments: [--userProperties, {}, --assetsDir, C:/Users/Hectiik/.gradle/caches/minecraft/assets, --assetIndex, 1.7.10, --accessToken, {REDACTED}, --version, 1.7.10, --tweakClass, cpw.mods.fml.common.launcher.FMLTweaker, --username, ForgeDevName] [09:59:15] [main/INFO] [LaunchWrapper]: Loading tweak class name cpw.mods.fml.common.launcher.FMLTweaker [09:59:15] [main/INFO] [LaunchWrapper]: Using primary tweak class name cpw.mods.fml.common.launcher.FMLTweaker [09:59:16] [main/INFO] [LaunchWrapper]: Calling tweak class cpw.mods.fml.common.launcher.FMLTweaker [09:59:16] [main/INFO] [FML]: Forge Mod Loader version 7.10.18.1180 for Minecraft 1.7.10 loading [09:59:16] [main/INFO] [FML]: Java is Java HotSpot 64-Bit Server VM, version 1.8.0_20, running on Windows 8:amd64:6.2, installed at C:\Program Files\Java\jre1.8.0_20 [09:59:16] [main/INFO] [FML]: Managed to load a deobfuscated Minecraft name- we are in a deobfuscated environment. Skipping runtime deobfuscation [09:59:16] [main/INFO] [LaunchWrapper]: Loading tweak class name cpw.mods.fml.common.launcher.FMLInjectionAndSortingTweaker [09:59:16] [main/INFO] [LaunchWrapper]: Loading tweak class name cpw.mods.fml.common.launcher.FMLDeobfTweaker [09:59:16] [main/INFO] [LaunchWrapper]: Calling tweak class cpw.mods.fml.common.launcher.FMLInjectionAndSortingTweaker Exception in thread "main" [09:59:16] [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:?] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_20] at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_20] at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_20] at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_20] at GradleStart.bounce(GradleStart.java:107) [start/:?] at GradleStart.startClient(GradleStart.java:100) [start/:?] at GradleStart.main(GradleStart.java:55) [start/:?] java.lang.ArrayIndexOutOfBoundsException: 0 at GradleStart.main(GradleStart.java:59) Java HotSpot 64-Bit Server VM warning: Using incremental CMS is deprecated and will likely be removed in a future release can someone please help me this. Thank you.