or go to C:\Users\vijay\AppData\Roaming\JDeveloper\system12.1.3.0.41.170120.1047\DefaultDomain\bin
setStartEnv.cmd go to below lines to set the required memory arguments.
@REM 32 bit JVM memory settings
set SERVER_MEM_ARGS_32=-Xms512m -Xmx1024m
set SERVER_MEM_ARGS_32HotSpot=-Xms512m -Xmx1024m -XX:PermSize=256m -XX:MaxPermSize=1024m
set SERVER_MEM_ARGS_32JRockit=-Xms512m -Xmx1024m
@REM 64 bit JVM memory settings