Java Refuses to Start - Could not reserve enough space for object heap

You're using a 32-bit OS, so you're going to be seeing limits on the total size due to that. Other answers have covered this in more detail, so I'll avoid repeating their information.

A behaviour that I noticed with our servers recently is that specifying a maximum heap size with -Xmx while not specifying a minimum heap size with -Xms would lead to Java's server VM immediately attempting to allocate all of the memory needed for the maximum heap size. And sure, if the app gets up to that heap size, that's the amount of memory that you'll need. But the chances are, your apps will be starting out with comparitively small heaps and may require the larger heap at some later point. Additionally specifying the minimum heap size will let you start your app start with a smaller heap and gradually grow that heap.

All of this isn't going to help you increase your maximum heap size, but I figured it might help, so...

As suggested in other responses the problem is causes by exhaustion of virtual address space. A 32bit linux userspace program is usually limited to 3GB of AS; the remaining 1GB is used by the kernel (rationale: since the top 1GB is kernel fixed mapping it's not necessary to touch the page table when serving syscalls).

RHEL kernels, however, implement the so called 4GB/4GB split where the full 4GB AS is available to userspace processes at cost of a slight runtime overhead (the kernel lives in a separate 4GB virtual AS)