无法在 java 进程上转储堆
我有一个我想调试的java进程。它的问题是它有太多打开的连接，因此运行 jmap 会失败，因为它无法连接到进程。 运行 jmap -F 会产生下一个错误：
Attaching to process ID 1772, please wait...
sun.jvm.hotspot.debugger.NoSuchSymbolException: Could not find symbol "gHotSpotVMTypeEntryTypeNameOffset" in any of the known library names (libjvm.so, libjvm_g.so, gamma_g)
at sun.jvm.hotspot.HotSpotTypeDataBase.lookupInProcess(HotSpotTypeDataBase.java:388)
at sun.jvm.hotspot.HotSpotTypeDataBase.getLongValueFromProcess(HotSpotTypeDataBase.java:369)
at sun.jvm.hotspot.HotSpotTypeDataBase.readVMTypes(HotSpotTypeDataBase.java:102)
at sun.jvm.hotspot.HotSpotTypeDataBase.<init>(HotSpotTypeDataBase.java:85)
at sun.jvm.hotspot.bugspot.BugSpotAgent.setupVM(BugSpotAgent.java:568)
at sun.jvm.hotspot.bugspot.BugSpotAgent.go(BugSpotAgent.java:494)
at sun.jvm.hotspot.bugspot.BugSpotAgent.attach(BugSpotAgent.java:332)
at sun.jvm.hotspot.tools.Tool.start(Tool.java:163)
at sun.jvm.hotspot.tools.HeapDumper.main(HeapDumper.java:77)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at sun.tools.jmap.JMap.runTool(JMap.java:179)
at sun.tools.jmap.JMap.main(JMap.java:110)
Debugger attached successfully.
可能是什么问题？是否可以在不重新启动进程的情况下解决该问题（重新启动后该错误可能会消失，所以我想避免它）。
I have a java process which I want to debug. The problem with it is that it has too many open connections, so running jmap fails because it can't connect to process.
Running jmap -F produces the next error:
Attaching to process ID 1772, please wait...
sun.jvm.hotspot.debugger.NoSuchSymbolException: Could not find symbol "gHotSpotVMTypeEntryTypeNameOffset" in any of the known library names (libjvm.so, libjvm_g.so, gamma_g)
at sun.jvm.hotspot.HotSpotTypeDataBase.lookupInProcess(HotSpotTypeDataBase.java:388)
at sun.jvm.hotspot.HotSpotTypeDataBase.getLongValueFromProcess(HotSpotTypeDataBase.java:369)
at sun.jvm.hotspot.HotSpotTypeDataBase.readVMTypes(HotSpotTypeDataBase.java:102)
at sun.jvm.hotspot.HotSpotTypeDataBase.<init>(HotSpotTypeDataBase.java:85)
at sun.jvm.hotspot.bugspot.BugSpotAgent.setupVM(BugSpotAgent.java:568)
at sun.jvm.hotspot.bugspot.BugSpotAgent.go(BugSpotAgent.java:494)
at sun.jvm.hotspot.bugspot.BugSpotAgent.attach(BugSpotAgent.java:332)
at sun.jvm.hotspot.tools.Tool.start(Tool.java:163)
at sun.jvm.hotspot.tools.HeapDumper.main(HeapDumper.java:77)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at sun.tools.jmap.JMap.runTool(JMap.java:179)
at sun.tools.jmap.JMap.main(JMap.java:110)
Debugger attached successfully.
What can be the problem? Can it be solved without restarting the process (It is possible the bug will disappear after restarting so I want to avoid it).
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冒着陈述显而易见的风险......
如果由于打开的连接太多而无法与调试器连接，这可能也是您试图找到的错误的根源。
尝试使用操作系统级实用程序来找出进程当前打开的文件/套接字/等。你给你一些线索告诉你从哪里开始寻找。如果这还不够，请在代码库中搜索打开文件/套接字的所有位置，并检查它们以确保它们具有始终的封闭
try / finally关闭文件/套接字。At the risk of stating the obvious ...
If you cannot connect with the debugger because too many connections are open, that is probably also at the root of the bug you are trying to find.
Try using an OS-level utility to find out what files / sockets / etc the process currently has open. That you give you some clues to tell you where to start looking. If that's not enough, search through your codebase for all places where files / sockets are opened, and examine them to make sure that they have an enclosing
try / finallythat will always close the file / socket.您可以使用 Sun 6 JDK 中的 VisualVM 进行连接吗？它使用不同的方法并允许您学习很多东西 - 这可能就足够了 - 但它不是一个调试器。
Can you use visualvm from the Sun 6 JDK to connect? It uses a different method and allows you to learn a lot - which may be enough - but is not a debugger.
对于Sun Jvm：
您可以尝试新的
如果 HotSpotDiagnostic 类在编译时不可见，则
您可以将具有 HotSpotDiagnosticMXBean.class 的 rt.jar 复制到其他位置。使用“添加外部 jar”在构建路径中引用复制的 jar。这允许您创建对象并获取堆转储。
For Sun Jvm :
You can try new
If HotSpotDiagnostic class is not visible at compile time,then
You can copy the rt.jar which has the HotSpotDiagnosticMXBean.class to a different location. Refer the copied jar in build path using "Add External jar". This allows you to create Object and get the Heap dump.