Direct answer:
A JVM, the version is 1.8. The
details are as follows:
The displayed information is the
java version (that is, the jvm version we usually say)
Java runtime environment version
JIT compilation environment
(JIT description)
Java HotSpot is a mixed-mode virtual machine. That is, it can both interpret the bytecode and compile the code to native machine code for faster execution. By configuring the -XX:+PrintCompilation parameter, you can see the information in the log file when the method is JIT compiled. JIT compilation happens at runtime - after a method has been run multiple times. When a method is needed, the HotSpot VM decides how to optimize the code.
In addition,
JIT is to improve the compilation performance. You don’t need to care about it when you are a beginner. When
you develop to an advanced level, you can read the book on the insider class of JVM.
You can recommend the book "In-depth Understanding of Java Virtual Machine" about JIT