When a method invocation is running while debugger is detached, this JDWP error is thrown after debugger is attached again and a method is invoked.

To reproduce:
A) In one terminal:
1) Unzip the attached project,
2) cd build/classes; java -Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=8777 -cp . minc.Main

B) In second terminal:
1) jdb -attach 8777
2) stop at minc.Main:34
3) "wait for breakpoint hit"
4) print m()
5) Press CTRL-C before the method invocation completes. (Treminal A will write "Method 'm' started 1 times and finished 0 times.")
6) Wait for "Method 'm' finished." message printed on terminal A
7) jdb -attach 8777
8) stop at minc.Main:34
9) "wait for breakpoint hit"
11) print m()
12) com.sun.jdi.InternalException: Unexpected JDWP Error: 502