Put the summary of the bug you're having here

What I expected to happen was...:
Describe what you thought should happen here

What actually happened was...:
Describe what happened here

Steps to Reproduce:
1. previously i tried to modify JVM arguments ,dont know if its orignal ,and i crashed ,then i redownloaded agn.and now crash agn,
-Xmx1G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalMode -XX:-UseAdaptiveSizePolicy -Xmn128M
2. i unticked the javaVM arguments after i keep cant get into my world or multiplayer,it keeps saying JVM arguments memory relevant things
3. so now i m experiencing this crash again ,im here to report this with attach