title: Why `sun.jvm.hotspot.debugger.DebuggerException: cannot open binary file`?
body: <p>In linux, I got a core file generated by java, it can't be opened by jvisualvm ,so I want to translate it to a heap dump file , but occured some error :</p>
  
  <pre><code>[root@root_test-1 game]$ jmap -J-d64 -dump:format=b,file=core.10255.dump java ./core.10255
  Attaching to core ./core.10255 from executable java, please wait...
  Error attaching to core file: cannot open binary file
  sun.jvm.hotspot.debugger.DebuggerException: cannot open binary file
          at sun.jvm.hotspot.debugger.linux.LinuxDebuggerLocal.attach0(Native Method)
          at sun.jvm.hotspot.debugger.linux.LinuxDebuggerLocal.attach(LinuxDebuggerLocal.java:286)
          at sun.jvm.hotspot.HotSpotAgent.attachDebugger(HotSpotAgent.java:673)
          at sun.jvm.hotspot.HotSpotAgent.setupDebuggerLinux(HotSpotAgent.java:611)
          at sun.jvm.hotspot.HotSpotAgent.setupDebugger(HotSpotAgent.java:337)
          at sun.jvm.hotspot.HotSpotAgent.go(HotSpotAgent.java:304)
          at sun.jvm.hotspot.HotSpotAgent.attach(HotSpotAgent.java:156)
          at sun.jvm.hotspot.tools.Tool.start(Tool.java:191)
          at sun.jvm.hotspot.tools.Tool.execute(Tool.java:118)
          at sun.jvm.hotspot.tools.HeapDumper.main(HeapDumper.java:83)
          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:497)
          at sun.tools.jmap.JMap.runTool(JMap.java:201)
          at sun.tools.jmap.JMap.main(JMap.java:130)
  </code></pre>
  
  <p>How to fix it?</p>