JHSDB(1) JDK Commands JHSDB(1)
NAME
jhsdb - attach to a Java process or launch a postmortem debugger to an-
alyze the content of a core dump from a crashed Java Virtual Machine
(JVM)
SYNOPSIS
jhsdb clhsdb [--pid pid | --exe executable --core coredump]
jhsdb hsdb [--pid pid | --exe executable --core coredump]
jhsdb debugd (--pid pid | --exe executable --core coredump) [options]
jhsdb jstack (--pid pid | --exe executable --core coredump | --connect
[server-id@]debugd-host) [options]
jhsdb jmap (--pid pid | --exe executable --core coredump | --connect
[server-id@]debugd-host) [options]
jhsdb jinfo (--pid pid | --exe executable --core coredump | --connect
[server-id@]debugd-host) [options]
jhsdb jsnap (--pid pid | --exe executable --core coredump | --connect
[server-id@]debugd-host) [options]
pid The process ID to which the jhsdb tool should attach. The
process must be a Java process. To get a list of Java processes
running on a machine, use the ps command or, if the JVM process-
es are not running in a separate docker instance, the jps com-
mand.
executable
The Java executable file from which the core dump was produced.
coredump
The core file to which the jhsdb tool should attach.
[server-id@]debugd-host
An optional server ID and the address of the remote debug server
(debugd).
options
The command-line options for a jhsdb mode. See Options for the
debugd Mode, Options for the jstack Mode, Options for the jmap
Mode, Options for the jinfo Mode, and Options for the jsnap
Mode.
Note:
Either the pid or the pair of executable and core files or the [server-
id@]debugd-host must be provided for debugd, jstack, jmap, jinfo and
jsnap modes.
DESCRIPTION
You can use the jhsdb tool to attach to a Java process or to launch a
postmortem debugger to analyze the content of a core-dump from a
crashed Java Virtual Machine (JVM). This command is experimental and
unsupported.
Note:
Attaching the jhsdb tool to a live process will cause the process to
hang and the process will probably crash when the debugger detaches.
The jhsdb tool can be launched in any one of the following modes:
jhsdb clhsdb
Starts the interactive command-line debugger.
jhsdb hsdb
Starts the interactive GUI debugger.
jhsdb debugd
Starts the remote debug server.
jhsdb jstack
Prints stack and locks information.
jhsdb jmap
Prints heap information.
jhsdb jinfo
Prints basic JVM information.
jhsdb jsnap
Prints performance counter information.
jhsdb command --help
Displays the options available for the command.
OPTIONS FOR THE DEBUGD MODE
--serverid server-id
An optional unique ID for this debug server. This is required
if multiple debug servers are run on the same machine.
--rmiport port
Sets the port number to which the RMI connector is bound. If
not specified a random available port is used.
--registryport port
Sets the RMI registry port. This option overrides the system
property 'sun.jvm.hotspot.rmi.port'. If not specified, the sys-
tem property is used. If the system property is not set, the
default port 1099 is used.
--hostname hostname
Sets the hostname the RMI connector is bound. The value could
be a hostname or an IPv4/IPv6 address. This option overrides
the system property 'java.rmi.server.hostname'. If not speci-
fied, the system property is used. If the system property is
not set, a system hostname is used.
OPTIONS FOR THE JINFO MODE
--flags
Prints the VM flags.
--sysprops
Prints the Java system properties.
no option
Prints the VM flags and the Java system properties.
OPTIONS FOR THE JMAP MODE
no option
Prints the same information as Solaris pmap.
--heap Prints the java heap summary.
--binaryheap
Dumps the java heap in hprof binary format.
--dumpfile name
The name of the dumpfile.
--histo
Prints the histogram of java object heap.
--clstats
Prints the class loader statistics.
--finalizerinfo
Prints the information on objects awaiting finalization.
OPTIONS FOR THE JSTACK MODE
--locks
Prints the java.util.concurrent locks information.
--mixed
Attempts to print both java and native frames if the platform
allows it.
OPTIONS FOR THE JSNAP MODE
--all Prints all performance counters.
JDK 21 2023 JHSDB(1)
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