1. export dump file

1.1 obtain PID( Two ways )

You can use the task manager to get

You can also use jconsole Indirect acquisition

• stay jdk Of bin In the directory jconsole.exe Execution can be
  
  

• If you don’t see the local process 、 There may be a problem with file permissions

  solve ：
  First through local java Code runs ：
  System.out.println(System.getProperties());
  View the properties java.io.tmpdir=C:\Users%USER%\AppData\Local\Temp
  notes : here %USER% Represents the operating system user name for the variable
  Enter this directory , See a hsperfdata_%USER% Catalog , Enter this directory
  

1.2 Use jmap export dump file

• Get into jdk / bin Catalog

jmap -dump:format=b,file=heap.dump <pid>
The current directory will generate heap.dump file

see JVM The number of instances of classes in memory and the amount of memory consumed

• start-up jvisualvm
  
• Import dump file
  
• Select file type and file
  
• Look at the number of examples 、 size 、 Retain ( Check for memory leaks )
  
• PS Reserved fields need to be configured