openjdk版本

openjdk version "1.8.0_161"
OpenJDK Runtime Environment (build 1.8.0_161-b14)
OpenJDK 64-Bit Server VM (build 25.161-b14, mixed mode)

執行jmap -heap 報錯

 jmap -heap  17694  
Attaching to process ID 17694, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 25.161
 
-b14

using parallel threads in the new generation.
using thread-local object allocation.
Concurrent Mark-Sweep GC

Heap Configuration:
   MinHeapFreeRatio         = 40
   MaxHeapFreeRatio         = 70
   MaxHeapSize              = 8589934592 (8192.0MB)
   NewSize                  = 1570308096 (1497.5625MB)
   MaxNewSize               = 1570308096
 
 (1497.5625MB)
   OldSize                  = 7019626496 (6694.4375MB)
   NewRatio                 = 2
   SurvivorRatio            = 8
   MetaspaceSize            = 21807104 (20.796875MB)
   CompressedClassSpaceSize = 1073741824 (1024.0MB)
   MaxMetaspaceSize         = 17592186044415 MB
   G1HeapRegionSize         = 0
 
 (0.0MB)

Heap Usage:
Exception in thread "main" java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at sun.tools.jmap.JMap.runTool(JMap.java:201)
        at sun.tools.jmap.JMap.main(JMap.java:130)
Caused by: java.lang.RuntimeException: unknown CollectedHeap type : class sun.jvm.hotspot.gc_interface.CollectedHeap
        at sun.jvm.hotspot.tools.HeapSummary.run(HeapSummary.java:144)
        at sun.jvm.hotspot.tools.Tool.startInternal(Tool.java:260)
        at sun.jvm.hotspot.tools.Tool.start(Tool.java:223)
        at sun.jvm.hotspot.tools.Tool.execute(Tool.java:118)
        at sun.jvm.hotspot.tools.HeapSummary.main(HeapSummary.java:49)
        ... 6 more

原因是機器缺少openjdk-debuginfo這個包 ，注意該包版本必須和jdk版本一致。

或者從下面網站找

http://debuginfo.centos.org/6/x86_64/ 

將rpm包下載到伺服器本地，手動安裝

rpm -ivh java-1.8.0-openjdk-debuginfo-1.8.0.161-3.b14.el6_9.x86_64.rpm