Description: There was a severe problem during mod loading that has caused the game to fail

net.minecraftforge.fml.common.LoaderException: java.lang.ClassNotFoundException: vazkii.psi.common.Psi
at net.minecraftforge.fml.common.LoadController.transition(LoadController.java:162)
at net.minecraftforge.fml.common.Loader.loadMods(Loader.java:543)
at net.minecraftforge.fml.client.FMLClientHandler.beginMinecraftLoading(FMLClientHandler.java:208)
at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:417)
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:329)
at net.minecraft.client.main.Main.main(SourceFile:124)
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: vazkii.psi.common.Psi
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:191)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at net.minecraftforge.fml.common.ModClassLoader.loadClass(ModClassLoader.java:65)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at net.minecraftforge.fml.common.FMLModContainer.constructMod(FMLModContainer.java:468)
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 com.google.common.eventbus.EventSubscriber.handleEvent(EventSubscriber.java:74)
at com.google.common.eventbus.SynchronizedEventSubscriber.handleEvent(SynchronizedEventSubscriber.java:47)
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:322)
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:304)
at com.google.common.eventbus.EventBus.post(EventBus.java:275)
at net.minecraftforge.fml.common.LoadController.sendEventToModContainer(LoadController.java:211)
at net.minecraftforge.fml.common.LoadController.propogateStateMessage(LoadController.java:189)
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 com.google.common.eventbus.EventSubscriber.handleEvent(EventSubscriber.java:74)
at com.google.common.eventbus.SynchronizedEventSubscriber.handleEvent(SynchronizedEventSubscriber.java:47)
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:322)
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:304)
at com.google.common.eventbus.EventBus.post(EventBus.java:275)
at net.minecraftforge.fml.common.LoadController.distributeStateMessage(LoadController.java:118)
at net.minecraftforge.fml.common.Loader.loadMods(Loader.java:512)
... 10 more
Caused by: java.lang.UnsupportedClassVersionError: vazkii/psi/common/Psi : Unsupported major.minor version 52.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.security.SecureClassLoader.defineClass(Unknown Source)
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:182)
... 38 more

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

-- System Details --
Details:
Minecraft Version: 1.8.9
Operating System: Windows 7 (amd64) version 6.1
Java Version: 1.7.0_79, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 1523344712 bytes (1452 MB) / 2077753344 bytes (1981 MB) up to 3151495168 bytes (3005 MB)
JVM Flags: 8 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx3G -Xms2G -XX:PermSize=512m -XX:MaxPermSize=1G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy
IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
FML: MCP 9.19 Powered by Forge 11.15.1.1722 4 mods loaded, 4 mods active
States: 'U' = Unloaded 'L' = Loaded 'C' = Constructed 'H' = Pre-initialized 'I' = Initialized 'J' = Post-initialized 'A' = Available 'D' = Disabled 'E' = Errored
UC mcp{9.19} Minecraft Coder Pack
UC FML{8.0.99.99} Forge Mod Loader
UC Forge{11.15.1.1722} Minecraft Forge
UE Psi{beta-11} Psi
Loaded coremods (and transformers):
GL info: ' Vendor: 'ATI Technologies Inc.' Version: '4.4.13283 Compatibility Profile Context 14.501.1003.0' Renderer: 'AMD Radeon HD 6570'

WOW! Nevermind about this. Updated from Java 7 to 8. Fixed it right up.