What is the evolution and change of the Java virtual machine?
- 王林forward
- 2023-04-26 22:55:061245browse
1. Sun Classic/Exact VM
Class VM (JDK 1.0)
The world’s first commercial Java virtual machine
Pure Execute Java code in interpreter mode
Object search based on handle
Exact VM (JDK 1.2)
Accurate memory management: the virtual machine can know the data at a certain location in the memory Specific type
2, HotSpot VM
Default virtual machine in Sun/OracleJDK and OpenJDK
The most widely used Java virtual machine
Since the HotSpot virtual machine is currently the most widely used and is currently the default virtual machine for OracleJDK and OpenJDK, the content analysis in the following article is mainly focused on this virtual machine.
Execute the java -version command on the terminal as follows:
$ java -version java version "1.8.0_191" Java(TM) SE Runtime Environment (build 1.8.0_191-b12) Java HotSpot(TM) 64-Bit Server VM (build 25.191-b12, mixed mode)
3. Mobile/Embedded VM
Java ME virtual machine
4. BEA JRockit/IBM J9 VM
These two virtual machines were once known as the "three major commercial Java virtual machines" together with the HotSpot virtual machine.
JRockit
Focus on server-side applications
Does not contain an interpreter, all codes are compiled and executed by a just-in-time compiler
J9 VM
Separation of duties and modularity are better than HotSpot VM
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