运行命令：

jmap -heap 6709

 

报错如下：

Attaching to process ID 6709, please wait...

sun.jvm.hotspot.debugger.NoSuchSymbolException: Could not find symbol "gHotSpotVMTypes" in any of the known library names (libjvm.so, libjvm_g.so, gamma_g)

at sun.jvm.hotspot.HotSpotTypeDataBase.lookupInProcess(HotSpotTypeDataBase.java:585)

at sun.jvm.hotspot.HotSpotTypeDataBase.readVMTypes(HotSpotTypeDataBase.java:150)

at sun.jvm.hotspot.HotSpotTypeDataBase.(HotSpotTypeDataBase.java:85)

at sun.jvm.hotspot.bugspot.BugSpotAgent.setupVM(BugSpotAgent.java:569)

at sun.jvm.hotspot.bugspot.BugSpotAgent.go(BugSpotAgent.java:493)

at sun.jvm.hotspot.bugspot.BugSpotAgent.attach(BugSpotAgent.java:331)

at sun.jvm.hotspot.tools.Tool.start(Tool.java:163)

at sun.jvm.hotspot.tools.HeapSummary.main(HeapSummary.java:40)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:606)

at sun.tools.jmap.JMap.runTool(JMap.java:197)

at sun.tools.jmap.JMap.main(JMap.java:128)

Debugger attached successfully.

sun.jvm.hotspot.tools.HeapSummary requires a java VM process/core!

 

 

报错原因：

　　根据错误提示，可以看出来，需要一个java jvm的核心进程。

　　明明PID就是我java进程的PID，进程编号呀。

 

错误原因：

　　PID不是你要查看的JAVA进程的PID，注意区分你到底要查看那个JVM进程。

 

解决方法：

　　查看java进程的PID

ps -ef | grep java

 

　　现在自己查看一下，就可以发现

　　6709是另一个位置的java进程。

　　19570才是 我们当前想要查看的JVM进程。

　　因为自己安装的java路径在/mnt/apps/soft/java路径 。配置的环境变量也是这个路径下的JDK.

 

　　所以运行jmap指定错误的PID就导致了开始的错误。

 

　　现在修改jmap指定的PID

jmap -heap 19570

 

运行成功：

Attaching to process ID 19570, please wait...

Debugger attached successfully.

Server compiler detected.

JVM version is 24.80-b11

using thread-local object allocation.

Parallel GC with 8 thread(s)

Heap Configuration:

MinHeapFreeRatio = 0

MaxHeapFreeRatio = 100

MaxHeapSize = 4164943872 (3972.0MB)

NewSize = 1310720 (1.25MB)

MaxNewSize = 17592186044415 MB

OldSize = 5439488 (5.1875MB)

NewRatio = 2

SurvivorRatio = 8

PermSize = 21757952 (20.75MB)

MaxPermSize = 85983232 (82.0MB)

G1HeapRegionSize = 0 (0.0MB)

Heap Usage:

PS Young Generation

Eden Space:

capacity = 1245708288 (1188.0MB)

used = 550338952 (524.844123840332MB)

free = 695369336 (663.155876159668MB)

44.17879830305825% used

From Space:

capacity = 68681728 (65.5MB)

used = 507920 (0.4843902587890625MB)

free = 68173808 (65.01560974121094MB)

0.7395271126550572% used

To Space:

capacity = 70254592 (67.0MB)

used = 0 (0.0MB)

free = 70254592 (67.0MB)

0.0% used

PS Old Generation

capacity = 217055232 (207.0MB)

used = 116954920 (111.53690338134766MB)

free = 100100312 (95.46309661865234MB)

53.88256201997471% used

PS Perm Generation

capacity = 85983232 (82.0MB)

used = 75303848 (71.81534576416016MB)

free = 10679384 (10.184654235839844MB)

87.57968995629287% used

40959 interned Strings occupying 4521736 bytes.

 

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