If you are Running Java program in Eclipse and ever tried playing with -Xmx parameter you know about those virtual machine initialization error e.g. "“Error occurred during initialization of VM; Could not reserve enough space for object heap”. This error usually occur when you to try to give your program, running on 32-bit JVM more than 1.4G of memory in Eclipse in Windows. It doesn't matter how much memory your machine have e.g. I have seen this error in laptops running 4GB of memory. The important thing which matter is whether JRE or JVM you are using with Eclipse is 32-bit or 64-bit. If you use 64-bit JRE in Eclipse, you can potentially allocate more than 1.4G of memory in Windows itself.