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arthas/en/_sources/jvm.md.txt

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jvm
===
[`sysenv` online tutorial](https://alibaba.github.io/arthas/arthas-tutorials?language=en&id=command-sysenv)
> Check the current JVM's info
### Usage
```
$ jvm
RUNTIME
--------------------------------------------------------------------------------------------------------------
MACHINE-NAME 37@ff267334bb65
JVM-START-TIME 2020-07-23 07:50:36
MANAGEMENT-SPEC-VERSION 1.2
SPEC-NAME Java Virtual Machine Specification
SPEC-VENDOR Oracle Corporation
SPEC-VERSION 1.8
VM-NAME Java HotSpot(TM) 64-Bit Server VM
VM-VENDOR Oracle Corporation
VM-VERSION 25.201-b09
INPUT-ARGUMENTS []
CLASS-PATH demo-arthas-spring-boot.jar
BOOT-CLASS-PATH /usr/lib/jvm/java-8-oracle/jre/lib/resources.jar:/usr/lib/jvm/java-8-oracle/j
re/lib/rt.jar:/usr/lib/jvm/java-8-oracle/jre/lib/sunrsasign.jar:/usr/lib/jvm/
java-8-oracle/jre/lib/jsse.jar:/usr/lib/jvm/java-8-oracle/jre/lib/jce.jar:/us
r/lib/jvm/java-8-oracle/jre/lib/charsets.jar:/usr/lib/jvm/java-8-oracle/jre/l
ib/jfr.jar:/usr/lib/jvm/java-8-oracle/jre/classes
LIBRARY-PATH /usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib
--------------------------------------------------------------------------------------------------------------
CLASS-LOADING
--------------------------------------------------------------------------------------------------------------
LOADED-CLASS-COUNT 7529
TOTAL-LOADED-CLASS-COUNT 7529
UNLOADED-CLASS-COUNT 0
IS-VERBOSE false
--------------------------------------------------------------------------------------------------------------
COMPILATION
--------------------------------------------------------------------------------------------------------------
NAME HotSpot 64-Bit Tiered Compilers
TOTAL-COMPILE-TIME 14921(ms)
--------------------------------------------------------------------------------------------------------------
GARBAGE-COLLECTORS
--------------------------------------------------------------------------------------------------------------
PS Scavenge name : PS Scavenge
[count/time (ms)] collectionCount : 7
collectionTime : 68
PS MarkSweep name : PS MarkSweep
[count/time (ms)] collectionCount : 1
collectionTime : 47
--------------------------------------------------------------------------------------------------------------
MEMORY-MANAGERS
--------------------------------------------------------------------------------------------------------------
CodeCacheManager Code Cache
Metaspace Manager Metaspace
Compressed Class Space
Copy Eden Space
Survivor Space
MarkSweepCompact Eden Space
Survivor Space
Tenured Gen
--------------------------------------------------------------------------------------------------------------
MEMORY
--------------------------------------------------------------------------------------------------------------
HEAP-MEMORY-USAGE init : 268435456(256.0 MiB)
[memory in bytes] used : 18039504(17.2 MiB)
committed : 181403648(173.0 MiB)
max : 3817865216(3.6 GiB)
NO-HEAP-MEMORY-USAGE init : 2555904(2.4 MiB)
[memory in bytes] used : 33926216(32.4 MiB)
committed : 35176448(33.5 MiB)
max : -1(-1 B)
--------------------------------------------------------------------------------------------------------------
OPERATING-SYSTEM
--------------------------------------------------------------------------------------------------------------
OS Linux
ARCH amd64
PROCESSORS-COUNT 3
LOAD-AVERAGE 29.53
VERSION 4.15.0-52-generic
--------------------------------------------------------------------------------------------------------------
THREAD
--------------------------------------------------------------------------------------------------------------
COUNT 30
DAEMON-COUNT 24
PEAK-COUNT 31
STARTED-COUNT 36
DEADLOCK-COUNT 0
--------------------------------------------------------------------------------------------------------------
FILE-DESCRIPTOR
--------------------------------------------------------------------------------------------------------------
MAX-FILE-DESCRIPTOR-COUNT 1048576
OPEN-FILE-DESCRIPTOR-COUNT 100
Affect(row-cnt:0) cost in 88 ms.
```
### Thread related
* COUNT: the count of active threads
* DAEMON-COUNT: the count of active daemon threads
* PEAK-COUNT: the maximum count of the live threads since JVM starts
* STARTED-COUNT: the total count of the created threads since JVM starts
* DEADLOCK-COUNT: the count of deadlocked threads
### File descriptor related
* MAX-FILE-DESCRIPTOR-COUNTthe count of max file descriptor JVM process can open
* OPEN-FILE-DESCRIPTOR-COUNTthe current count of file descriptor JVM process open