We are all experienced Java Developer , Think about why you have to learn JVM? [ interview ? tuning ? Pack to force ? ]

For whatever reason , Anyway, you have to learn . How to learn well ?

Everyone for JVM I don't know the same thing , It's about how to cut in

Now that we've all learned Java, Let's start with that Java Start talking about , It's also literacy , After all, not everyone is a computer major

first-class Java developer

• What is? Java?
• programing language
• Computer [ Hardware ] The language you can understand
• So JM What is it? ?
• JDK JRE JyM

JVM What should we learn

Java The source code file ——> javac compiler ——> Class file ——> Java Virtual Machine

• Source to class file
• Class file to virtual machine ( Class loading mechanism )
• Run time data area (Run -Time Data Areas)
• JVM Memory model
• Garbage Collect ( Garbage collection )

If a worker wants to do a good job, he must sharpen his tools first

After all the previous analysis and learning , We know about JVM A lot of knowledge , For example, version information , Class loading , Pile up , Method area , Garbage collection, etc , But I always feel insecure , The reason is that you don't see something real .

This section mainly talks about how to make the content straight Show us in front of us , Including how to make some corresponding settings .

• JVM Parameters
• Common commands
• Commonly used tools
• Execution engine
• Recognitions JVM
  

performance optimization

JVM It can be divided into non optimization level and code level .

At the code level , You can optimize it with bytecode instructions , Like a loop statement , You can extract code that is not related to the loop out of the loop body , So there's no need to repeat the code at the bytecode level .

At the non code level , In general, it can be accessed from memory 、gc as well as cpu Optimize the occupancy rate, etc .

Be careful ,JVM Tuning is a long and complex process , And in many cases ,JVM It doesn't need to be optimized , because VM It has done a lot of internal optimization operations .

So today we're going to start with memory 、gc as well as cpu this 3 I'd like to talk to you in three aspects - Let's talk about it JVM The optimization of the , But we should pay attention not to tuning and tuning .

• Memory
• GC
• CFU High occupancy
• JVM Performance optimization guidelines
• common problem

JVM From introduction to enchantment with notes

JVM And performance optimization knowledge points