Java Tools Tutorials - Herong's Tutorial Notes - Version 5.32, by Dr. Herong Yang

Java Tools Tutorials - Herong's Tutorial Notes

∟'jdb' - The Java Debugger

∟'jdb' - Java Debugger Command and Options

"jdb": A command line tool that allows you to debug a Java application interactively with in a command line mode. "javac" is distributed as part of the Sun JDK package. It has the following syntax:

jdb [options] main_class_name
jdb [options] -attach <address> 

where "options" is a list of options, "main_class_name" is a the name of the main class of a Java application, and "address" is the debugging connection address of a running Java application.

As you can see from the syntax, there are two ways of running "jdb":

1. Running "jdb" to launch a Java application and start a debug session on that application.

2. Running "jdb" to connect to a separately launched Java application and start a debug session on that application.

Commonly used options are:

• "-help" - Displays a short help text.
• "-verbose" - Generates verbose output to standard output.
• "-classpath classpath" - Specifies a list of path names where the launcher will search for compiled type definitions.
• "-Dproperty=value" - Defines a new system property, which can be accessed by the application.
• "-launch" - Launches the debugged application immediately upon startup of jdb. This option removes the need for using the run command. The target 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 cont to continue execution.

Note that in order to use all debugging commands, the target application must be compiled with "-g" option, which will generate all debugging information, including source file, line number, and local variables, into the class file.

Last update: 2015.

Table of Contents

 About This Book

 Java Tools Terminology

 Installing Java 8 on Windows

 'javac' - The Java Program Compiler

 'java' - The Java Program Launcher

►'jdb' - The Java Debugger

►'jdb' - Java Debugger Command and Options

 Starting a Debugging Session with 'jdb'

 Debugging Applications with Separate 'jdb' Sessions

 Debugging Java Applications Remotely

 Listing Debugging Commands with 'help' Command

 PrimeNumberSeeker.java - Multi-Thread Sample Program

 Starting Debugging Session on a Multi-Thread Application

 Stepping through Statements of a Child Thread

 Checking Variable Values in a Debugging Session

 Debugging the Main Thread of a Multi-Thread Application

 Switching Execution Threads in a Debugging Session

 Suspending Main Thread to Debug Child Thread

 'jconsole' - Java Monitoring and Management Console

 'jstat' - JVM Statistics Monitoring Tool

 JVM Troubleshooting Tools

 jvisualvm (Java VisualVM) - JVM Visual Tool

 'jar' - The JAR File Tool

 'javap' - The Java Class File Disassembler

 'keytool' - Public Key Certificate Tool

 'native2ascii' - Native-to-ASCII Encoding Converter

 Outdated Tutorials

 References

 PDF Printing Version

'jdb' - Java Debugger Command and Options - Updated in 2017, by Dr. Herong Yang