[MC-20394] Crash When Hitting "Multiplayer"

Put the summary of the bug you're having here

What I expected to happen was...:
It woudl take me to the server list menu

What actually happened was...:
I crashed upon hitting "multiplayer"

Steps to Reproduce:
1. Download NEW Launcher
2. Hit Multiplayer
3. Crash

Description: Updating screen events

java.lang.ClassFormatError: Truncated class file
	at java.lang.ClassLoader.findBootstrapClass(Native Method)
	at java.lang.ClassLoader.findBootstrapClassOrNull(Unknown Source)
	at java.lang.ClassLoader.loadClass(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 bli.a(SourceFile:259)
	at avv.a(SourceFile:71)
	at bli.a(SourceFile:503)