Locate the file: setDomainEnv.cmd which should be at:
[JDev Install Dir]\jdeveloper\system\system11.1.1.0.31.51.88\DefaultDomain\bin
There find the line:set MEM_MAX_PERM_SIZE=-XX:MaxPermSize=128m
and change it to:set MEM_MAX_PERM_SIZE=-XX:MaxPermSize=512m