High CPU usage issue positioning

(1) top command - "check out the highest CPU usage PID number.

(2) top -H p PID number - "CPU utilization can check out the list of all threads (thread number are PID column).

(3) jstack xxxx (process ID) - "lists the current process stack of all threads.

(4) the previous thread turn into a hexadecimal number to pinpoint the specified thread, you can view the corresponding stack.