Commonly used management tools for JVM virtual machines

1. Command line tools

1. jps is
   equivalent to the ps (tasklist in windows process) of the Linux operating system, which is used to display the java process number.
   Usage:
   jps [-option]
   Parameters:
   -l: display the full class name
   -q: omit the class name and only display the port number
   -v: display the parameters of the virtual machine
   -m: display the parameters of the running main class
2. jstat
   displays class loading information,
   memory distribution, garbage collection, jit editing information, class loading information, etc.
   jsta - gcutil 端口号 次数
3. Jinfo can also
   jinfo -flag 端口号
   view or modify a parameter of the virtual machine
   java -XX:+PrintFlagsFinal
4. jmap
   generates snapshot information
   jmap -dump:format=b,file=d:\a.bin 8008
5. Jhat
   analyzes the classes in the snapshot.
   jhat d:\a.bin
   All class information will appear when accessing the local port 7000.
6. jstack
   jstack [option] vmid
   -l Display additional lock information
   -F Mandatory
   -m C/C++ stack can be displayed if local method is called

#用来打印thread信息
Map<Thread, StackTraceElement[]>map =  Thread.getAllStackTraces();
       for(Map.Entry<Thread, StackTraceElement[] >en : map.entrySet()){
    
    
           Thread t = en.getKey();
           StackTraceElement[] v = en.getValue();
           System.out.println("Thread:"  + t.getName());
           for(StackTraceElement s : v){
    
    
               System.out.println("\t" + s.toString());
           }