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*** 1,6 **** ! .\" Copyright (c) 1994, 2019, Oracle and/or its affiliates. All rights reserved. .\" DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. .\" .\" This code is free software; you can redistribute it and/or modify it .\" under the terms of the GNU General Public License version 2 only, as .\" published by the Free Software Foundation. --- 1,7 ---- ! '\" t ! .\" Copyright (c) 1995, 2013, Oracle and/or its affiliates. All rights reserved. .\" DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. .\" .\" This code is free software; you can redistribute it and/or modify it .\" under the terms of the GNU General Public License version 2 only, as .\" published by the Free Software Foundation.
*** 17,263 **** .\" .\" Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA .\" or visit www.oracle.com if you need additional information or have any .\" questions. .\" ! .\" Automatically generated by Pandoc 2.3.1 .\" ! .TH "JDB" "1" "2018" "JDK 13" "JDK Commands" ! .hy ! .SH NAME ! .PP ! jdb \- find and fix bugs in Java platform programs ! .SH SYNOPSIS ! .PP ! \f[CB]jdb\f[R] [\f[I]options\f[R]] [\f[I]classname\f[R]] ! [\f[I]arguments\f[R]] ! .TP ! .B \f[I]options\f[R] ! This represents the \f[CB]jdb\f[R] command\-line options. ! See \f[B]Options for the jdb command\f[R]. ! .RS ! .RE ! .TP ! .B \f[I]classname\f[R] ! This represents the name of the main class to debug. ! .RS ! .RE ! .TP ! .B \f[I]arguments\f[R] ! This represents the arguments that are passed to the \f[CB]main()\f[R] ! method of the class. ! .RS ! .RE ! .SH DESCRIPTION ! .PP ! The Java Debugger (JDB) is a simple command\-line debugger for Java ! classes. ! The \f[CB]jdb\f[R] command and its options call the JDB. ! The \f[CB]jdb\f[R] command demonstrates the Java Platform Debugger ! Architecture and provides inspection and debugging of a local or remote ! JVM. ! .SH START A JDB SESSION ! .PP ! There are many ways to start a JDB session. ! The most frequently used way is to have the JDB launch a new JVM with ! the main class of the application to be debugged. ! Do this by substituting the \f[CB]jdb\f[R] command for the \f[CB]java\f[R] ! command in the command line. ! For example, if your application\[aq]s main class is \f[CB]MyClass\f[R], ! then use the following command to debug it under the JDB: ! .RS ! .PP ! \f[CB]jdb\ MyClass\f[R] ! .RE ! .PP ! When started this way, the \f[CB]jdb\f[R] command calls a second JVM with ! the specified parameters, loads the specified class, and stops the JVM ! before executing that class\[aq]s first instruction. ! .PP ! Another way to use the \f[CB]jdb\f[R] command is by attaching it to a JVM ! that\[aq]s already running. ! Syntax for starting a JVM to which the \f[CB]jdb\f[R] command attaches ! when the JVM is running is as follows. ! This loads in\-process debugging libraries and specifies the kind of ! connection to be made. ! .RS ! .PP ! \f[CB]java\ \-agentlib:jdwp=transport=dt_socket,server=y,suspend=n\ MyClass\f[R] ! .RE ! .PP ! You can then attach the \f[CB]jdb\f[R] command to the JVM with the ! following command: ! .RS ! .PP ! \f[CB]jdb\ \-attach\ 8000\f[R] ! .RE ! .PP ! 8000 is the address of the running JVM. ! .PP ! The \f[CB]MyClass\f[R] argument isn\[aq]t specified in the \f[CB]jdb\f[R] ! command line in this case because the \f[CB]jdb\f[R] command is connecting ! to an existing JVM instead of launching a new JVM. ! .PP ! There are many other ways to connect the debugger to a JVM, and all of ! them are supported by the \f[CB]jdb\f[R] command. ! The Java Platform Debugger Architecture has additional documentation on ! these connection options. ! .SH BREAKPOINTS ! .PP ! Breakpoints can be set in the JDB at line numbers or at the first ! instruction of a method, for example: ! .IP \[bu] 2 ! The command \f[CB]stop\ at\ MyClass:22\f[R] sets a breakpoint at the first ! instruction for line 22 of the source file containing \f[CB]MyClass\f[R]. ! .IP \[bu] 2 ! The command \f[CB]stop\ in\ java.lang.String.length\f[R] sets a breakpoint ! at the beginning of the method \f[CB]java.lang.String.length\f[R]. ! .IP \[bu] 2 ! The command \f[CB]stop\ in\ MyClass.<clinit>\f[R] uses \f[CB]<clinit>\f[R] ! to identify the static initialization code for \f[CB]MyClass\f[R]. ! .PP ! When a method is overloaded, you must also specify its argument types so ! that the proper method can be selected for a breakpoint. ! For example, \f[CB]MyClass.myMethod(int,java.lang.String)\f[R] or ! \f[CB]MyClass.myMethod()\f[R]. ! .PP ! The \f[CB]clear\f[R] command removes breakpoints using the following ! syntax: \f[CB]clear\ MyClass:45\f[R]. ! Using the \f[CB]clear\f[R] or \f[CB]stop\f[R] command with no argument ! displays a list of all breakpoints currently set. ! The \f[CB]cont\f[R] command continues execution. ! .SH STEPPING ! .PP ! The \f[CB]step\f[R] command advances execution to the next line whether ! it\[aq]s in the current stack frame or a called method. ! The \f[CB]next\f[R] command advances execution to the next line in the ! current stack frame. ! .SH EXCEPTIONS ! .PP ! When an exception occurs for which there isn\[aq]t a \f[CB]catch\f[R] ! statement anywhere in the throwing thread\[aq]s call stack, the JVM ! typically prints an exception trace and exits. ! When running under the JDB, however, control returns to the JDB at the ! offending throw. ! You can then use the \f[CB]jdb\f[R] command to diagnose the cause of the ! exception. ! .PP ! Use the \f[CB]catch\f[R] command to cause the debugged application to stop ! at other thrown exceptions, for example: ! \f[CB]catch\ java.io.FileNotFoundException\f[R] or \f[CB]catch\f[R] ! \f[CB]mypackage.BigTroubleException\f[R]. ! Any exception that\[aq]s an instance of the specified class or subclass ! stops the application at the point where the exception is thrown. ! .PP ! The \f[CB]ignore\f[R] command negates the effect of an earlier ! \f[CB]catch\f[R] command. ! The \f[CB]ignore\f[R] command doesn\[aq]t cause the debugged JVM to ignore ! specific exceptions, but only to ignore the debugger. ! .SH OPTIONS FOR THE JDB COMMAND ! .PP ! When you use the \f[CB]jdb\f[R] command instead of the \f[CB]java\f[R] ! command on the command line, the \f[CB]jdb\f[R] command accepts many of ! the same options as the \f[CB]java\f[R] command. ! .PP ! The following options are accepted by the \f[CB]jdb\f[R] command: ! .TP ! .B \f[CB]\-help\f[R] ! Displays a help message. ! .RS ! .RE ! .TP ! .B \f[CB]\-sourcepath\f[R] \f[I]dir1\f[R]\f[CB]:\f[R]\f[I]dir2\f[R]\f[CB]:\f[R]... ! Uses the specified path to search for source files in the specified ! path. ! If this option is not specified, then use the default path of dot ! (\f[CB]\&.\f[R]). ! .RS ! .RE ! .TP ! .B \f[CB]\-attach\f[R] \f[I]address\f[R] ! Attaches the debugger to a running JVM with the default connection ! mechanism. ! .RS ! .RE ! .TP ! .B \f[CB]\-listen\f[R] \f[I]address\f[R] ! Waits for a running JVM to connect to the specified address with a ! standard connector. ! .RS ! .RE ! .TP ! .B \f[CB]\-listenany\f[R] ! Waits for a running JVM to connect at any available address using a ! standard connector. ! .RS ! .RE ! .TP ! .B \f[CB]\-launch\f[R] ! Starts the debugged application immediately upon startup of the ! \f[CB]jdb\f[R] command. ! The \f[CB]\-launch\f[R] option removes the need for the \f[CB]run\f[R] ! command. ! The debugged application is launched and then stopped just before the ! initial application class is loaded. ! At that point, you can set any necessary breakpoints and use the ! \f[CB]cont\f[R] command to continue execution. ! .RS ! .RE ! .TP ! .B \f[CB]\-listconnectors\f[R] ! Lists the connectors available in this JVM. ! .RS ! .RE ! .TP ! .B \f[CB]\-connect\f[R] \f[I]connector\-name\f[R]\f[CB]:\f[R]\f[I]name1\f[R]\f[CB]=\f[R]\f[I]value1\f[R].... ! Connects to the target JVM with the named connector and listed argument ! values. ! .RS ! .RE ! .TP ! .B \f[CB]\-dbgtrace\f[R] [\f[I]flags\f[R]] ! Prints information for debugging the \f[CB]jdb\f[R] command. ! .RS ! .RE ! .TP ! .B \f[CB]\-tclient\f[R] ! Runs the application in the Java HotSpot VM client. ! .RS ! .RE ! .TP ! .B \f[CB]\-tserver\f[R] ! Runs the application in the Java HotSpot VM server. ! .RS ! .RE ! .TP ! .B \f[CB]\-J\f[R]\f[I]option\f[R] ! Passes \f[I]option\f[R] to the JVM, where option is one of the options ! described on the reference page for the Java application launcher. ! For example, \f[CB]\-J\-Xms48m\f[R] sets the startup memory to 48 MB. ! See \f[I]Overview of Java Options\f[R] in \f[B]java\f[R]. ! .RS ! .RE ! .PP ! The following options are forwarded to the debuggee process: ! .TP ! .B \f[CB]\-v\f[R] or \f[CB]\-verbose\f[R][\f[CB]:\f[R]\f[I]class\f[R]|\f[CB]gc\f[R]|\f[CB]jni\f[R]] ! Turns on the verbose mode. ! .RS ! .RE ! .TP ! .B \f[CB]\-D\f[R]\f[I]name\f[R]\f[CB]=\f[R]\f[I]value\f[R] ! Sets a system property. ! .RS ! .RE ! .TP ! .B \f[CB]\-classpath\f[R] \f[I]dir\f[R] ! Lists directories separated by colons in which to look for classes. ! .RS ! .RE ! .TP ! .B \f[CB]\-X\f[R] \f[I]option\f[R] ! A nonstandard target JVM option. ! .RS ! .RE ! .PP ! Other options are supported to provide alternate mechanisms for ! connecting the debugger to the JVM that it\[aq]s to debug. --- 18,267 ---- .\" .\" Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA .\" or visit www.oracle.com if you need additional information or have any .\" questions. .\" ! .\" Arch: generic ! .\" Software: JDK 8 ! .\" Date: 21 November 2013 ! .\" SectDesc: Basic Tools ! .\" Title: jdb.1 .\" ! .if n .pl 99999 ! .TH jdb 1 "21 November 2013" "JDK 8" "Basic Tools" ! .\" ----------------------------------------------------------------- ! .\" * Define some portability stuff ! .\" ----------------------------------------------------------------- ! .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ! .\" http://bugs.debian.org/507673 ! .\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html ! .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ! .ie \n(.g .ds Aq \(aq ! .el .ds Aq ' ! .\" ----------------------------------------------------------------- ! .\" * set default formatting ! .\" ----------------------------------------------------------------- ! .\" disable hyphenation ! .nh ! .\" disable justification (adjust text to left margin only) ! .ad l ! .\" ----------------------------------------------------------------- ! .\" * MAIN CONTENT STARTS HERE * ! .\" ----------------------------------------------------------------- ! ! .SH NAME ! jdb \- Finds and fixes bugs in Java platform programs\&. ! .SH SYNOPSIS ! .sp ! .nf ! ! \fBjdb\fR [\fIoptions\fR] [\fIclassname\fR] [\fIarguments\fR] ! .fi ! .sp ! .TP ! \fIoptions\fR ! Command-line options\&. See Options\&. ! .TP ! \fIclass\fRname ! Name of the main class to debug\&. ! .TP ! \fIarguments\fR ! Arguments passed to the \f3main()\fR method of the class\&. ! .SH DESCRIPTION ! The Java Debugger (JDB) is a simple command-line debugger for Java classes\&. The \f3jdb\fR command and its options call the JDB\&. The \f3jdb\fR command demonstrates the Java Platform Debugger Architecture (JDBA) and provides inspection and debugging of a local or remote Java Virtual Machine (JVM)\&. See Java Platform Debugger Architecture (JDBA) at http://docs\&.oracle\&.com/javase/8/docs/technotes/guides/jpda/index\&.html ! .SS START\ A\ JDB\ SESSION ! There are many ways to start a JDB session\&. The most frequently used way is to have JDB launch a new JVM with the main class of the application to be debugged\&. Do this by substituting the \f3jdb\fR command for the \f3java\fR command in the command line\&. For example, if your application\&'s main class is \f3MyClass\fR, then use the following command to debug it under JDB: ! .sp ! .nf ! \f3jdb MyClass\fP ! .fi ! .nf ! \f3\fP ! .fi ! .sp ! When started this way, the \f3jdb\fR command calls a second JVM with the specified parameters, loads the specified class, and stops the JVM before executing that class\&'s first instruction\&. ! .PP ! Another way to use the \f3jdb\fR command is by attaching it to a JVM that is already running\&. Syntax for starting a JVM to which the \f3jdb\fR command attaches when the JVM is running is as follows\&. This loads in-process debugging libraries and specifies the kind of connection to be made\&. ! .sp ! .nf ! \f3java \-agentlib:jdwp=transport=dt_socket,server=y,suspend=n MyClass\fP ! .fi ! .nf ! \f3\fP ! .fi ! .sp ! You can then attach the \f3jdb\fR command to the JVM with the following command: ! .sp ! .nf ! \f3jdb \-attach 8000\fP ! .fi ! .nf ! \f3\fP ! .fi ! .sp ! The \f3MyClass\fR argument is not specified in the \f3jdb\fR command line in this case because the \f3jdb\fR command is connecting to an existing JVM instead of launching a new JVM\&. ! .PP ! There are many other ways to connect the debugger to a JVM, and all of them are supported by the \f3jdb\fR command\&. The Java Platform Debugger Architecture has additional documentation on these connection options\&. ! .SS BASIC\ JDB\ COMMANDS ! The following is a list of the basic \f3jdb\fR commands\&. The JDB supports other commands that you can list with the \f3-help\fR option\&. ! .TP ! help or ? ! The \f3help\fR or \f3?\fR commands display the list of recognized commands with a brief description\&. ! .TP ! run ! After you start JDB and set breakpoints, you can use the \f3run\fR command to execute the debugged application\&. The \f3run\fR command is available only when the \f3jdb\fR command starts the debugged application as opposed to attaching to an existing JVM\&. ! .TP ! cont ! Continues execution of the debugged application after a breakpoint, exception, or step\&. ! .TP ! print ! Displays Java objects and primitive values\&. For variables or fields of primitive types, the actual value is printed\&. For objects, a short description is printed\&. See the dump command to find out how to get more information about an object\&. ! ! \fINote:\fR To display local variables, the containing class must have been compiled with the \f3javac -g\fR option\&. ! ! The \f3print\fR command supports many simple Java expressions including those with method invocations, for example: ! .sp ! .nf ! \f3print MyClass\&.myStaticField\fP ! .fi ! .nf ! \f3print myObj\&.myInstanceField\fP ! .fi ! .nf ! \f3print i + j + k (i, j, k are primities and either fields or local variables)\fP ! .fi ! .nf ! \f3print myObj\&.myMethod() (if myMethod returns a non\-null)\fP ! .fi ! .nf ! \f3print new java\&.lang\&.String("Hello")\&.length()\fP ! .fi ! .nf ! \f3\fP ! .fi ! .sp ! ! .TP ! dump ! For primitive values, the \f3dump\fR command is identical to the \f3print\fR command\&. For objects, the \f3dump\fR command prints the current value of each field defined in the object\&. Static and instance fields are included\&. The \f3dump\fR command supports the same set of expressions as the \f3print\fR command\&. ! .TP ! threads ! List the threads that are currently running\&. For each thread, its name and current status are printed and an index that can be used in other commands\&. In this example, the thread index is 4, the thread is an instance of \f3java\&.lang\&.Thread\fR, the thread name is \f3main\fR, and it is currently running\&. ! .sp ! .nf ! \f34\&. (java\&.lang\&.Thread)0x1 main running\fP ! .fi ! .nf ! \f3\fP ! .fi ! .sp ! ! .TP ! thread ! Select a thread to be the current thread\&. Many \f3jdb\fR commands are based on the setting of the current thread\&. The thread is specified with the thread index described in the threads command\&. ! .TP ! where ! The \f3where\fR command with no arguments dumps the stack of the current thread\&. The \f3where\fR\f3all\fR command dumps the stack of all threads in the current thread group\&. The \f3where\fR\f3threadindex\fR command dumps the stack of the specified thread\&. ! ! If the current thread is suspended either through an event such as a breakpoint or through the \f3suspend\fR command, then local variables and fields can be displayed with the \f3print\fR and \f3dump\fR commands\&. The \f3up\fR and \f3down\fR commands select which stack frame is the current stack frame\&. ! .SS BREAKPOINTS ! Breakpoints can be set in JDB at line numbers or at the first instruction of a method, for example: ! .TP 0.2i ! \(bu ! The command \f3stop at MyClass:22\fR sets a breakpoint at the first instruction for line 22 of the source file containing \f3MyClass\fR\&. ! .TP 0.2i ! \(bu ! The command \f3stop in java\&.lang\&.String\&.length\fR sets a breakpoint at the beginning of the method \f3java\&.lang\&.String\&.length\fR\&. ! .TP 0.2i ! \(bu ! The command \f3stop in MyClass\&.<clinit>\fR uses \f3<clinit>\fR to identify the static initialization code for \f3MyClass\fR\&. ! .PP ! When a method is overloaded, you must also specify its argument types so that the proper method can be selected for a breakpoint\&. For example, \f3MyClass\&.myMethod(int,java\&.lang\&.String)\fR or \f3MyClass\&.myMethod()\fR\&. ! .PP ! The \f3clear\fR command removes breakpoints using the following syntax: \f3clear MyClass:45\fR\&. Using the \f3clear\fR or \f3stop\fR command with no argument displays a list of all breakpoints currently set\&. The \f3cont\fR command continues execution\&. ! .SS STEPPING ! The \f3step\fR command advances execution to the next line whether it is in the current stack frame or a called method\&. The \f3next\fR command advances execution to the next line in the current stack frame\&. ! .SS EXCEPTIONS ! When an exception occurs for which there is not a \f3catch\fR statement anywhere in the throwing thread\&'s call stack, the JVM typically prints an exception trace and exits\&. When running under JDB, however, control returns to JDB at the offending throw\&. You can then use the \f3jdb\fR command to diagnose the cause of the exception\&. ! .PP ! Use the \f3catch\fR command to cause the debugged application to stop at other thrown exceptions, for example: \f3catch java\&.io\&.FileNotFoundException\fR or \f3catch\fR\f3mypackage\&.BigTroubleException\fR\&. Any exception that is an instance of the specified class or subclass stops the application at the point where it is thrown\&. ! .PP ! The \f3ignore\fR command negates the effect of an earlier \f3catch\fR command\&. The \f3ignore\fR command does not cause the debugged JVM to ignore specific exceptions, but only to ignore the debugger\&. ! .SH OPTIONS ! When you use the \f3jdb\fR command instead of the \f3java\fR command on the command line, the \f3jdb\fR command accepts many of the same options as the \f3java\fR command, including \f3-D\fR, \f3-classpath\fR, and \f3-X\fR options\&. The following list contains additional options that are accepted by the \f3jdb\fR command\&. ! .PP ! Other options are supported to provide alternate mechanisms for connecting the debugger to the JVM it is to debug\&. For additional documentation about these connection alternatives, see Java Platform Debugger Architecture (JPDA) at http://docs\&.oracle\&.com/javase/8/docs/technotes/guides/jpda/index\&.html ! .TP ! -help ! .br ! Displays a help message\&. ! .TP ! -sourcepath \fIdir1:dir2: \&. \&. \&.\fR ! .br ! Uses the specified path to search for source files in the specified path\&. If this option is not specified, then use the default path of dot (\&.)\&. ! .TP ! -attach \fIaddress\fR ! .br ! Attaches the debugger to a running JVM with the default connection mechanism\&. ! .TP ! -listen \fIaddress\fR ! .br ! Waits for a running JVM to connect to the specified address with a standard connector\&. ! .TP ! -launch ! .br ! Starts the debugged application immediately upon startup of JDB\&. The \f3-launch\fR option removes the need for the \f3run\fR command\&. The debugged application is launched and then stopped just before the initial application class is loaded\&. At that point, you can set any necessary breakpoints and use the \f3cont\fR command to continue execution\&. ! .TP ! -listconnectors ! .br ! List the connectors available in this JVM\&. ! .TP ! -connect connector-name:\fIname1=value1\fR ! .br ! Connects to the target JVM with the named connector and listed argument values\&. ! .TP ! -dbgtrace [\fIflags\fR] ! .br ! Prints information for debugging the \f3jdb\fR command\&. ! .TP ! -tclient ! .br ! Runs the application in the Java HotSpot VM client\&. ! .TP ! -tserver ! .br ! Runs the application in the Java HotSpot VM server\&. ! .TP ! -J\fIoption\fR ! .br ! Passes \f3option\fR to the JVM, where option is one of the options described on the reference page for the Java application launcher\&. For example, \f3-J-Xms48m\fR sets the startup memory to 48 MB\&. See java(1)\&. ! .SH OPTIONS\ FORWARDED\ TO\ THE\ DEBUGGER\ PROCESS ! .TP ! -v -verbose[:\fIclass\fR|gc|jni] ! .br ! Turns on verbose mode\&. ! .TP ! -D\fIname\fR=\fIvalue\fR ! .br ! Sets a system property\&. ! .TP ! -classpath \fIdir\fR ! .br ! Lists directories separated by colons in which to look for classes\&. ! .TP ! -X\fIoption\fR ! .br ! Nonstandard target JVM option\&. ! .SH SEE\ ALSO ! .TP 0.2i ! \(bu ! javac(1) ! .TP 0.2i ! \(bu ! java(1) ! .TP 0.2i ! \(bu ! javap(1) ! .RE ! .br ! 'pl 8.5i ! 'bp
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