Debug Java Applications using JPDA in Eclipse

JVM tools interface defines that program being debugged should provide VM for debugging.

IDEs such as Eclipse, implement JDI (Java Debug Interface). JDI is a high level interface to define information related to remote debug requests.

-Xdebug - Enables debugging information

JDWP (Java Debug Wire protocol): format of debug information and requests (communication channel)
Xrunjdwp:transport=dt_socket,address=8787,server=y,suspend=n

Xrunjdwp -
Loads JDWP in the target VM (communicate with debugger application)

transport -
The socket being used

server-
y - yes for target application to listen to a debugger to attach

address -
transport address for the connection

suspend -
n - no  for target VM to be suspended until debugger application connects

Remote debugging in Eclipse 

Run > Debug Configurations > Remote Java Application > Create new debug configuration and specify the port (address given above)