At first glance thought: your port is already in use by another program, you can not connect the target virtual machine, not exactly.
netstat -ano
Connected to the target VM, address: '127.0.0.1:6151', transport: 'socket' 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99, myThread: true test-------------------- mainThread: true mainThread: false Disconnected from the target VM, address: '127.0.0.1:6151', transport: 'socket'
When the Java debugger debug port connection to the JVM, it displays the following message:
Connected to the target VM, address: '127.0.0.1:6151', transport: 'socket'
Similarly, when the program terminates, the following message is displayed, indicating the debugger has disconnected from the port:
Disconnected from the target VM, address: '127.0.0.1:6151', transport: 'socket'