OS within an OS

Would it be possible to make my own mini OS inside a java application? Over the pass few days I've been working on UI stuff and then I realized I basically implemented my own blackbox environment which made me start to think that with a few modifications i could easily make it into a mini OS

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There is no emulation. An emulator simulates hardware in software.

I beg to differ. I can cite several pieces of production level code at work where the JVM is simulates the hardware in the software.