Debugging applications - IntelliJ IDEA in Action - page 207

remote application is sending debugging information. The number entered here
is arbitrary, but there must be nothing else running on the port, including other
Java applications with debugging enabled.

Don't confuse the debugging port number with your application server's
port number. The debugging port number in the Run/Debug Configu-
rations window is the port number the debugger uses to communicate
with the application. This number should be the same as the one speci-
fied through the -Xrunjdwp switch when you launch the server. This has
nothing to do with the port number on which your application server is
handling HTTP requests (such as 80 or 8080).

WARNING

Debugging via shared memory
Windows users have the option of using shared memory, rather than a socket, for
communication between the application and the debugger. If you select this
option on the Remote tab of the Run/Debug Configurations dialog, you'll be
asked to enter the name of the shared memory segment as specified when you
launched your application. In theory, there is a speed advantage to communicat-
ing in this manner, but your mileage may vary. Note that the shared memory
transport option only works when you're debugging an application running on
the same machine as IDEA .

Connecting to a remote application for debugging
Just as you would when debugging a local application, select the Run/Debug con-
figuration you've created for your remote debugging session on the Remote tab
of the Run/Debug Configurations dialog and click the Debug icon on the main
toolbar or press Shift+F9 . The debugger will attempt to attach itself to the appli-
cation using the settings specified in the configuration. If it's unable to do so for
any reason, such as if the program isn't running, you'll be dutifully informed.

Setting up IDEA as a debugging server
Rather than have IDEA connect to your process, you can flip things around and
have the application contact IDEA when something goes wrong. To do this, select
Listen , rather than Attach , as the debugger mode on the Remote tab of the Run/
Debug Configurations dialog, and pass the required VM parameters when
launching your application. When the condition you've set up (such as an
uncaught exception) occurs on the remote application, it will attempt to contact
IDEA and establish a debugging session.