Java virtual machine (abbreviated as JVM) is a fictional computer, which is realized by simulating various computer functions on the actual computer. It has its own perfect hardware architecture (such as processor, stack, register, etc.). ) and the corresponding instruction system. The purpose of using "Java Virtual Machine" program is to support programs that are independent of the operating system and can run in any system. Because of the competitive strategy, Microsoft doesn't bundle JVM in Windows XP, so it can only download it online. VM (virtual manufacturing) host is actually the abbreviation of VMware host. Virtual manufacturing of VM: its essence is to unify the modeling of production processes such as design and manufacturing with the goal of global optimization of new products and their manufacturing systems, and to simulate the whole future manufacturing process of products and its influence on product design in real time and in parallel at the product design stage, and to predict product performance, product manufacturing cost and feasible manufacturing of products. One is for compatibility. The other is to create one or more computers on a computer. I hope it helps you.