How to debug an Android APK on a Genymotion emulator from a Linux command line?

Question

I am using a Genymotion (VirtualBox) Android emulator. When I'm trying to attach a JDB to a running Android app from a command line, I get a java.io.IOException: handshake failed - connection prematurally closed delight, namely:

$ adb jdwp
...
1720
1744
^C
$ adb forward tcp:1234 jdwp:1744
$ adb forward --list
192.168.56.105:5555 tcp:1234 jdwp:1744

$ ss -t -a | grep 1234
LISTEN 0      128        127.0.0.1:1234           0.0.0.0:*           

$ ifconfig
...
vboxnet0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.56.1  netmask 255.255.255.0  broadcast 192.168.56.255
        inet6 fe80::800:27ff:fe00:0  prefixlen 64  scopeid 0x20<link>
        ether 0a:00:27:00:00:00  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 243  bytes 48382 (47.2 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

$ jdb -attach localhost:1234
Picked up _JAVA_OPTIONS: -Dawt.useSystemAAFontSettings=on -Dswing.aatext=true
java.io.IOException: handshake failed - connection prematurally closed
        at jdk.jdi/com.sun.tools.jdi.SocketTransportService.handshake(SocketTransportService.java:142)
        at jdk.jdi/com.sun.tools.jdi.SocketTransportService.attach(SocketTransportService.java:255)
        at jdk.jdi/com.sun.tools.jdi.GenericAttachingConnector.attach(GenericAttachingConnector.java:119)
        at jdk.jdi/com.sun.tools.jdi.SocketAttachingConnector.attach(SocketAttachingConnector.java:83)
        at jdk.jdi/com.sun.tools.example.debug.tty.VMConnection.attachTarget(VMConnection.java:519)
        at jdk.jdi/com.sun.tools.example.debug.tty.VMConnection.open(VMConnection.java:328)
        at jdk.jdi/com.sun.tools.example.debug.tty.Env.init(Env.java:63)
        at jdk.jdi/com.sun.tools.example.debug.tty.TTY.main(TTY.java:1095)

Fatal error:
Unable to attach to target VM.

Using the Android Studio IDE/GUI, however, I am able to attach a debugger with a click of the button. Can't debug with the Android Studio giving my situation.

score 0 · Answer 1 · answered May 30 '20 at 02:33

It appears that it's the Android Studio itself causing this problem... Also killing the adb server with the Android Studio running, makes the adb server to automatically restart. The solution here is not to run the Android Studio doing a JDB session from the command line.

How to debug an Android APK on a Genymotion emulator from a Linux command line?

1 Answers1