Just did a fresh install ( Forge 36.2.20) and the game crashes almost immediately after launch. I am using the most recent version of java (java 8 321)
Exception in thread "main" [18:01:03] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:-1]: java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
[18:01:03] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:-1]: at cpw.mods.modlauncher.LaunchServiceHandlerDecorator.launch(LaunchServiceHandlerDecorator.java:39)
[18:01:03] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:-1]: at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:54)
[18:01:03] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:-1]: at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:72)
[18:01:03] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:-1]: at cpw.mods.modlauncher.Launcher.run(Launcher.java:82)
[18:01:03] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:-1]: at cpw.mods.modlauncher.Launcher.main(Launcher.java:66)
[18:01:03] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:-1]: Caused by: java.lang.reflect.InvocationTargetException
[18:01:03] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:-1]: at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[18:01:03] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:-1]: at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
[18:01:03] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:-1]: at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
[18:01:03] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:-1]: at java.lang.reflect.Method.invoke(Unknown Source)
[18:01:03] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:-1]: at net.minecraftforge.fml.loading.FMLClientLaunchProvider.lambda$launchService$0(FMLClientLaunchProvider.java:51)
[18:01:03] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:-1]: at cpw.mods.modlauncher.LaunchServiceHandlerDecorator.launch(LaunchServiceHandlerDecorator.java:37)
[18:01:03] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:-1]: ... 4 more
[18:01:03] [main/INFO] [STDERR/]: [java.lang.Throwable:printStackTrace:-1]: Caused by: java.lang.NoSuchMethodError: sun.security.util.ManifestEntryVerifier.<init>(Ljava/util/jar/Manifest;)V
[18:01:03] [main/INFO] [STDERR/]: [java.lang.Throwable:printStackTrace:-1]: at cpw.mods.modlauncher.SecureJarHandler.createCodeSource(SecureJarHandler.java:66)
[18:01:03] [main/INFO] [STDERR/]: [java.lang.Throwable:printStackTrace:-1]: at cpw.mods.modlauncher.TransformingClassLoader$DelegatedClassLoader.findClass(TransformingClassLoader.java:275)
[18:01:03] [main/INFO] [STDERR/]: [java.lang.Throwable:printStackTrace:-1]: at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:136)
[18:01:03] [main/INFO] [STDERR/]: [java.lang.Throwable:printStackTrace:-1]: at cpw.mods.modlauncher.TransformingClassLoader.loadClass(TransformingClassLoader.java:98)
[18:01:03] [main/INFO] [STDERR/]: [java.lang.Throwable:printStackTrace:-1]: at java.lang.ClassLoader.loadClass(Unknown Source)
[18:01:03] [main/INFO] [STDERR/]: [java.lang.Throwable:printStackTrace:-1]: at net.minecraft.crash.CrashReport.func_71504_g(CrashReport.java:72)
[18:01:03] [main/INFO] [STDERR/]: [java.lang.Throwable:printStackTrace:-1]: at net.minecraft.crash.CrashReport.<init>(CrashReport.java:38)
[18:01:03] [main/INFO] [STDERR/]: [java.lang.Throwable:printStackTrace:-1]: at net.minecraft.crash.CrashReport.func_230188_h_(CrashReport.java:248)
[18:01:03] [main/INFO] [STDERR/]: [java.lang.Throwable:printStackTrace:-1]: at net.minecraft.client.main.Main.main(Main.java:122)
[18:01:03] [main/INFO] [STDERR/]: [java.lang.Throwable:printStackTrace:-1]: ... 10 more