Java virtual machine performance monitoring and troubleshooting tools, virtual machine troubleshooting

Java virtual machine performance monitoring and troubleshooting tools, virtual machine troubleshooting

1. jdk command line tool

1) jps: Virtual Machine Process status Tool

Jps [option] [hostid]

Main parameters:

2) jstat: Virtual Machine statistics monitoring tool

Jstat-<option> [-t] [-h <lines>] <vmid> [<interval> [<count>]

Main parameters:

 

For example, if the gc information of process 8675 is queried twice every 8675 ms, jstat-gc 1000 2

 

 

3) jinfo: Java configuration information tool

Allows you to view and modify VM parameters in real time.

Usage:

Jinfo [option] <pid>

(To connect to running process)

Jinfo [option] <executable <core>

(To connect to a core file)

Jinfo [option] [server_id @] <remote server IP or hostname>

(To connect to remote debug server)

For example, query the maximum allocable size of the new generation memory in the Java heap area of the VM.

 

 

4) jmap: Java memory image tool

Usage:

Jmap [option] <pid>

(To connect to running process)

Jmap [option] <executable <core>

(To connect to a core file)

Jmap [option] [server_id @] <remote server IP or hostname>

(To connect to remote debug server)

Common parameters:

 

Example:

 

 

5) jhat: Virtual Machine heap dump snapshot analysis tool

The built-in http server can be used to analyze dump files generated by jmap.

For example:

Access http: // 192.168.10.92: 7007/

 

 

6) jstack: generate the thread snapshot (threaddump or javacore file) at the current time of the VM ).

Usage:

Jstack [-l] <pid>

(To connect to running process)

Jstack-F [-m] [-l] <pid>

(To connect to a hung process)

Jstack [-m] [-l] <executable> <core>

(To connect to a core file)

Jstack [-m] [-l] [server_id @] <remote server IP or hostname>

(To connect to a remote debug server)

Main parameters:

 

7) hsdis: Code disassembly generated by JIT

2. visualization tools

Jconsole and visualvm (omitted)

 

References

Deep understanding of Java Virtual Machine: JVM advanced features and best practices (version 2nd)