“Failed to attach to the remote VM” connecting jdb

Question

I’ve been trying to connect jdb to the android emulator for a little while, and have been met repeatedly with:

jdb -sourcepath ./src -attach localhost:8700

java.io.IOException: shmemBase_attach failed: The system cannot find the file specified
        at com.sun.tools.jdi.SharedMemoryTransportService.attach0(Native Method)
        at com.sun.tools.jdi.SharedMemoryTransportService.attach(SharedMemoryTransportService.java:90)
        at com.sun.tools.jdi.GenericAttachingConnector.attach(GenericAttachingConnector.java:98)
        at com.sun.tools.jdi.SharedMemoryAttachingConnector.attach(SharedMemoryAttachingConnector.java:45)
        at com.sun.tools.example.debug.tty.VMConnection.attachTarget(VMConnection.java:358)
        at com.sun.tools.example.debug.tty.VMConnection.open(VMConnection.java:168)
        at com.sun.tools.example.debug.tty.Env.init(Env.java:64)
        at com.sun.tools.example.debug.tty.TTY.main(TTY.java:1010)

Fatal error:
Unable to attach to target VM.

Not so great. What's the best way of getting round this? I'm running on Windows 7 64bit.

Answer 1

Currently this is working for me -- making a socket rather than a shared memory connection.

>jdb –sourcepath .\src -connect com.sun.jdi.SocketAttach:hostname=localhost,port=8700

Beforehand you need to do some setup -- for example, see this set of useful details on setting up a non-eclipse debugger. It includes a good tip for setting your initial breakpoint -- create or edit a jdb.ini file in your home directory, with content like:

stop at com.mine.of.package.some.AClassIn:14

and they'll get loaded and deferred until connection.

edit: forgot to reference Herong Yang's page.

Answer 2

Try quitting Android Studio.

I had a similar problem on the Mac due to the ADB daemon already running. Once you quit any running daemons, you should see output similar to the following:

$ adb -d jdwp
28462
1939
^C
$ adb -d forward tcp:7777 jdwp:1939
$ jdb -attach localhost:7777 -sourcepath ./src
Set uncaught java.lang.Throwable
Set deferred uncaught java.lang.Throwable
Initializing jdb ...
> 

See my other answer to a similar question for more details and how to start/stop the daemon.

Answer 3

In order to debug application follow this steps:

Open the application on the device.

Find the PID with jdwp (make sure that 'android:debuggable' is set to true in the manifest):

adb jdwp

Start JVM with the following parameters:

java -agentlib:jdwp=transport=dt_shmem,server=y,address=<port> <class>

Expected output for this command:

Listening for transport dt_shmem at address: <port>

Use jdb to attach the application:

jdb -attach <port>

If jdb successful attached we will see the jdb cli.

Example:

> adb jdwp
  12300
> java -agentlib:jdwp=transport=dt_shmem,server=y,address=8700 com.app.app
  Listening for transport dt_shmem at address: 8700
> jdb -attach 8700
  main[1]

Answer 4

Answer #1: Map localhost in your hosts file, as I linked to earlier. Just to be sure.

Answer #2: If you're using shared memory, bit-size could easily become an issue. Make sure you're using the same word width everywhere.