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."

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."

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."

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." 2 along with this work; if not, write to the Free Software Foundation,

." Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

."

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." questions.

."

.TH jstat 1 "02 Jun 2010"

.LP

.SH "Name"

jstat \- Java Virtual Machine Statistics Monitoring Tool

.LP

.SH "SYNOPSIS"

.LP

.LP

.nf

\f3

.fl

\fP\f3jstat\fP [ \f2generalOption\fP | \f2outputOptions\fP \f2vmid\fP [\f2interval\fP[s|ms] [\f2count\fP]] ]

.fl

.fi

.LP

.SH "PARAMETERS"

.LP

.LP

.RS 3

.TP 3

generalOption 

A single general command\-line option (\-help, \-options, or \-version) 

.TP 3

outputOptions 

One or more output options, consisting of a single \f2statOption\fP, plus any of the \-t, \-h, and \-J options. 

.TP 3

vmid 

Virtual machine identifier, a string indicating the target Java virtual machine (JVM). The general syntax is 

.nf

\f3

.fl

[\fP\f4protocol\fP\f3:][//]\fP\f4lvmid\fP[@\f2hostname\fP[:\f2port\fP]/\f2servername\fP]

.fl

.fi

The syntax of the vmid string largely corresponds to the syntax of a URI. The \f2vmid\fP can vary from a simple integer representing a local JVM to a more complex construction specifying a communications protocol, port number, and other implementation\-specific values. See Virtual Machine Identifier for details. 

.TP 3

interval[s|ms] 

Sampling interval in the specified units, seconds (s) or milliseconds (ms). Default units are milliseconds.\  Must be a positive integer.\  If specified, \f3jstat\fP will produce its output at each interval. 

.TP 3

count 

Number of samples to display. Default value is infinity; that is, \f3jstat\fP displays statistics until the target JVM terminates or the \f3jstat\fP command is terminated.\  Must be a positive integer. 

.RE

.LP

.SH "DESCRIPTION"

.LP

.LP

.LP

The \f3jstat\fP tool displays performance statistics for an instrumented HotSpot Java virtual machine (JVM). The target JVM is identified by its virtual machine identifier, or \f2vmid\fP option described below.

.LP

.LP

\f3NOTE\fP: This utility is unsupported and may not be available in future versions of the JDK. It is not currently available on Windows 98 and Windows ME. platforms.

.br

.LP

.SS 

VIRTUAL MACHINE IDENTIFIER

.LP

.RS 3

.LP

.LP

The syntax of the \f2vmid\fP string largely corresponds to the syntax of a URI:

.LP

.nf

\f3

.fl

[\fP\f4protocol\fP\f3:][//]\fP\f4lvmid\fP[@\f2hostname\fP][:\f2port\fP][/\f2servername\fP]

.fl

.fi

.LP

.RS 3

.TP 3

protocol 

The communications protocol. If the \f2protocol\fP is omitted and a \f2hostname\fP is not specified, the default protocol is a platform specific optimized local protocol. If the \f2protocol\fP is omitted and a \f2hostname\fP is specified, then the default protocol is \f3rmi\fP. 

.TP 3

lvmid 

The local virtual machine identifier for the target JVM. The \f2lvmid\fP is a platform\-specific value that uniquely identifies a JVM on a system. The \f2lvmid\fP is the only required component of a virtual machine identifier. The \f2lvmid\fP is typically, but not necessarily, the operating system's process identifier for the target JVM process. You can use the jps(1) command to determine the \f2lvmid\fP. Also, you can determine \f2lvmid\fP on Unix platforms with the \f3ps\fP command, and on Windows with the Windows Task Manager. 

.TP 3

hostname 

A hostname or IP address indicating the target host. If \f2hostname\fP is omitted, then the target host is the local host. 

.TP 3

port 

The default port for communicating with the remote server. If the \f2hostname\fP is omitted or the \f2protocol\fP specifies an optimized, local protocol, then \f2port\fP is ignored. Otherwise, treatment of the \f2port\fP parameter is implementation specific. For the default \f3rmi\fP protocol, the \f2port\fP indicates the port number for the rmiregistry on the remote host. If \f2port\fP is omitted, and \f2protocol\fP indicates \f3rmi\fP, then the default rmiregistry port (1099) is used. 

.TP 3

servername 

The treatment of this parameter depends on implementation. For the optimized local protocol, this field is ignored. For the \f3rmi\fP protocol, it represents the name of the RMI remote object on the remote host. 

.RE

.LP

.RE

.SH "OPTIONS"

.LP

.LP

.LP

The \f3jstat\fP command supports two types of options, general options and output options. General options cause \f3jstat\fP to display simple usage and version information. Output options determine the content and format of the statistical output.

.br

.LP

.LP

\f3NOTE\fP: All options, and their functionality are subject to change or removal in future releases.

.LP

.SS 

GENERAL OPTIONS

.LP

.LP

If you specify one of the general options, you cannot specify any other option or parameter.

.LP

.RS 3

.TP 3

\-help 

Display help message. 

.TP 3

\-version 

Display version information. 

.TP 3

\-options 

Display list of statistics options. See the Output Options section below. 

.RE

.LP

.SS 

OUTPUT OPTIONS

.LP

.RS 3

.LP

.LP

If you do not specify a general option, then you can specify output options. Output options determine the content and format of \f3jstat\fP's output, and consist of a single \f2statOption\fP, plus any of the other output options (\-h, \-t, and \-J).\  The \f2statOption\fP must come first.

.LP

.LP

Output is formatted as a table, with columns are separated by spaces. A header row with titles describes the columns.\  Use the \f3\-h\fP option to set the frequency at which the header is displayed.\  Column header names are generally consistent between the different options. In general, if two options provide a column with the same name, then the data source for the two columns are the same.

.LP

.LP

Use the \f3\-t\fP option to display a time stamp column, labeled \f2Timestamp\fP as the first column of output. The \f2Timestamp\fP column contains the elapsed time, in seconds, since startup of the target JVM. The resolution of the time stamp is dependent on various factors and is subject to variation due to delayed thread scheduling on heavily loaded systems.

.LP

.LP

Use the \f2interval\fP and \f2count\fP parameters to determine how frequently and how many times, respectively, \f3jstat\fP displays its output.

.LP

.LP

\f3NOTE\fP: You are advised not to write scripts to parse \f3jstat's\fP output since the format may change in future releases. If you choose to write scripts that parse \f3jstat\fP output, expect to modify them for future releases of this tool.

.LP

.RS 3

.TP 3

\-statOption 

Determines the statistics information that \f3jstat\fP displays. The following table lists the available options.\  Use the \f3\-options\fP general option to display the list of options for a particular platform installation.

.br

.br

.LP

.TS

.if \n+(b.=1 .nr d. \n(.c-\n(c.-1

.de 35

.ps \n(.s

.vs \n(.vu

.in \n(.iu

.if \n(.u .fi

.if \n(.j .ad

.if \n(.j=0 .na

..

.nf

.nr #~ 0

.if n .nr #~ 0.6n

.ds #d .d

.if \(ts\n(.z\(ts\(ts .ds #d nl

.fc

.nr 33 \n(.s

.rm 80 81

.nr 34 \n(.lu

.eo

.am 81

.br

.di a+

.35

.ft \n(.f

.ll \n(34u*1u/3u

.if \n(.l<\n(81 .ll \n(81u

.in 0

Statistics on the behavior of the class loader.

.br

.di

.nr a| \n(dn

.nr a- \n(dl

..

.ec \

.eo

.am 81

.br

.di b+

.35

.ft \n(.f

.ll \n(34u*1u/3u

.if \n(.l<\n(81 .ll \n(81u

.in 0

Statistics of the behavior of the HotSpot Just\-in\-Time compiler.

.br

.di

.nr b| \n(dn

.nr b- \n(dl

..

.ec \

.eo

.am 81

.br

.di c+

.35

.ft \n(.f

.ll \n(34u*1u/3u

.if \n(.l<\n(81 .ll \n(81u

.in 0

Statistics of the behavior of the garbage collected heap.

.br

.di

.nr c| \n(dn

.nr c- \n(dl

..

.ec \

.eo

.am 81

.br

.di d+

.35

.ft \n(.f

.ll \n(34u*1u/3u

.if \n(.l<\n(81 .ll \n(81u

.in 0

Statistics of the capacities of the generations and their corresponding spaces.

.br

.di

.nr d| \n(dn

.nr d- \n(dl

..

.ec \

.eo

.am 81

.br

.di e+

.35

.ft \n(.f

.ll \n(34u*1u/3u

.if \n(.l<\n(81 .ll \n(81u

.in 0

Summary of garbage collection statistics (same as \f3\-gcutil\fP), with the cause of the last and current (if applicable) garbage collection events.

.br

.di

.nr e| \n(dn

.nr e- \n(dl

..

.ec \

.eo

.am 81

.br

.di f+

.35

.ft \n(.f

.ll \n(34u*1u/3u

.if \n(.l<\n(81 .ll \n(81u

.in 0

Statistics of the behavior of the new generation.

.br

.di

.nr f| \n(dn

.nr f- \n(dl

..

.ec \

.eo

.am 81

.br

.di g+

.35

.ft \n(.f

.ll \n(34u*1u/3u

.if \n(.l<\n(81 .ll \n(81u

.in 0

Statistics of the sizes of the new generations and its corresponding spaces.

.br

.di

.nr g| \n(dn

.nr g- \n(dl

..

.ec \

.eo

.am 81

.br

.di h+

.35

.ft \n(.f

.ll \n(34u*1u/3u

.if \n(.l<\n(81 .ll \n(81u

.in 0

Statistics of the behavior of the old and permanent generations.

.br

.di

.nr h| \n(dn

.nr h- \n(dl

..

.ec \

.eo

.am 81

.br

.di i+

.35

.ft \n(.f

.ll \n(34u*1u/3u

.if \n(.l<\n(81 .ll \n(81u

.in 0

Statistics of the sizes of the old generation.

.br

.di

.nr i| \n(dn

.nr i- \n(dl

..

.ec \

.eo

.am 81

.br

.di j+

.35

.ft \n(.f

.ll \n(34u*1u/3u

.if \n(.l<\n(81 .ll \n(81u

.in 0

Statistics of the sizes of the permanent generation.

.br

.di

.nr j| \n(dn

.nr j- \n(dl

..

.ec \

.eo

.am 81

.br

.di k+

.35

.ft \n(.f

.ll \n(34u*1u/3u

.if \n(.l<\n(81 .ll \n(81u

.in 0

Summary of garbage collection statistics.

.br

.di

.nr k| \n(dn

.nr k- \n(dl

..

.ec \

.eo

.am 81

.br

.di l+

.35

.ft \n(.f

.ll \n(34u*1u/3u

.if \n(.l<\n(81 .ll \n(81u

.in 0

HotSpot compilation method statistics.

.br

.di

.nr l| \n(dn

.nr l- \n(dl

..

.ec \

.35

.nf

.ll \n(34u

.nr 80 0

.nr 38 \w\f3Option\fP

.if \n(80<\n(38 .nr 80 \n(38

.nr 38 \wclass

.if \n(80<\n(38 .nr 80 \n(38

.nr 38 \wcompiler

.if \n(80<\n(38 .nr 80 \n(38

.nr 38 \wgc

.if \n(80<\n(38 .nr 80 \n(38

.nr 38 \wgccapacity

.if \n(80<\n(38 .nr 80 \n(38

.nr 38 \wgccause

.if \n(80<\n(38 .nr 80 \n(38

.nr 38 \wgcnew

.if \n(80<\n(38 .nr 80 \n(38

.nr 38 \wgcnewcapacity

.if \n(80<\n(38 .nr 80 \n(38

.nr 38 \wgcold

.if \n(80<\n(38 .nr 80 \n(38

.nr 38 \wgcoldcapacity

.if \n(80<\n(38 .nr 80 \n(38

.nr 38 \wgcpermcapacity

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.nr 38 \wgcutil

.if \n(80<\n(38 .nr 80 \n(38

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.if \n(80<\n(38 .nr 80 \n(38

.80

.rm 80

.nr 81 0

.nr 38 \w\f3Displays...\fP

.if \n(81<\n(38 .nr 81 \n(38

.81

.rm 81

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