Currently, Ignite on start creates JVM instance internally, but
it never stops it. Also, it currently can not work with already started
So when you start Ignite the first time, it loads JVM, when you stop
and unload it, the JVM remains loaded in process memory. When
you start Ignite again, it discovers that JVM was already loaded, and
as it can not work with pre-loaded JVM, it just returns you the error.
To solve the issue, the following ticket should be implemented , but
currently, it is not. As a workaround you may try to call
JNI_DestroyJavaVM() after you have unloaded Ignite, I'm not sure
of the result though. This is simply is not a use case we have tested.