Could not reserve enough space for object heap

What does ``Could not reserve enough space for object heap'' mean?
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If you try to run the java compiler or the java virtual machine and you
encounter an error such as

Error occurred during initialization of VM
Could not reserve enough space for object heap
Could not create the Java virtual machine.

then you have tried to run the command from a non-login shell.  The error is
due to the proper ulimit resources not being set for your current shell.  If
the shell you run the command in was a login shell, then it would have sourced
/etc/profile and set the ulimits correctly.

To fix the problem, make sure you are in a login shell (for example, a
terminal started with the '-ls' option).  Also, see 12.11 for similar
side-effects.