The so-called virtual machine, is a virtual machine. Ta It is a software used to execute a series of virtual computer instructions, in general virtual machines can be divided into system virtual machine and program virtual machine, Visual Box, Vmare belong to the system virtual machine. They are completely simulations of the physical computer and provide a software platform to run the operating system. The typical representative of a program virtual machine is a Java Virtual machine, which is designed for executing a single computer program, and the instructions executed in a Java virtual machine are called Java bytecode directives. Whether it is a system virtual machine or a program virtual machine, the software running on it is limited to the resources provided by the virtual machine. Java development So far, there have been a lot of virtual machines, the original Sun used a classic Java virtual machine, to now the most widely cited is the hotspot virtual machine, in addition to Sun, there is Bea JRockit, At present, JRockit and hotspot are under the Oracle revenue, there is a trend of integration.
The basic structure of a Java virtual machine
How the Java Virtual machine Works