Invalid initial and maximum heap size in JVM - How to fix

I was getting "Invalid initial heap size: -Xms=1024M" while starting JVM and even after changing maximum heap size from 1024 to 512M it keep crashing by telling "Invalid initial heap size: -Xms=512m , Could not create the Java virtual machine". I check almost everything starting from checking how much physical memory my machine has to any typo in JVM parameters, only to find out that instead of M, I had put MB there. Java accepts both small case and the capital case for Kilo, Mega, and Gigs. you can use m or M, g or G etc but never used MB, GB or KB.  Similar problem can occur with maximum heap size specified by -Xmx. Also from Java 6 update 18, there is change on default heap size in JVM.  

Read more »