Java and Cygwin: a difficult relation

[Lapo Luchini <l dot luchini at andxor dot it>]

In the company I and Alessandro (in cc) work for there is a Java
application that uses gamin in order to receive file alteration events.
Main development platform is FreeBSD and, as gamin has no pure-Java
client available, we used a smallish JNI wrapper around the libgamin
client; it works flawlessly.

The problem is now, of course, to do it all on Windows.
gamin seems to compile and work, on cygwin, with a few patches; this
seemed to be the hard part, but in fact reveals to be the easier one.
The other problem is that from JNI you can't simply call a cygwin DLL,
as it wouldn't load his cygwin1.dll dependency correctly and surely dump.

I had a similar problem, a few months ago: calling a .NET managed code
from Java.
In that case, I reversed the approach: instead of importing an external
DLL using JNI, I instantiated the Java Virtual Machine itself inside the
.NET program, and "register" the local function as a static method of
the Java class.

This is the approach we pursued since this very morning, "almost"
succeeding in it.
"almost", unfortunately.

Calling the C function is not a problem, it even does a couple debug
printf with no problem.
But as soon as the C function calls a libgamin method (FAMOpen, the very
first one), it all fails miserably.
Anyone has an idea why? Is it a random bug or a fundamental problem of
the way cygwin1.dll works (like in the case of direct JNI)?

Follows the error itself:

#
# An unexpected error has been detected by HotSpot Virtual Machine:
#
#  EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x610ad945, pid=1280,
tid=1084
#
# Java VM: Java HotSpot(TM) Client VM (1.5.0_06-b05 mixed mode, sharing)
# Problematic frame:
# C  [cygwin1.dll+0xad945]
#
# An error report file with more information is saved as hs_err_pid1280.log
#
# If you would like to submit a bug report, please visit:
#   http://java.sun.com/webapps/bugreport/crash.jsp
#

And an excerpt of hs_err_pid1280.log (the relevant stack frame):

Stack: [0x00030000,0x00230000),  sp=0x0022e9ec,  free space=2042k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code,
C=native code)
C  [cygwin1.dll+0xad945]
C  [cygwin1.dll+0x8dd7f]
C  [launcherS.exe+0x3048]
C  [launcherS.exe+0x11e4]
j  com.andxor.gamin.FAMConnection.FAMOpen()J+0
j  com.andxor.gamin.FAMConnection.<init>()V+25
j  FAMTest.main([Ljava/lang/String;)V+27
v  ~StubRoutines::call_stub
V  [jvm.dll+0x845a9]
V  [jvm.dll+0xd9317]
V  [jvm.dll+0x8447a]
V  [jvm.dll+0x8b44a]
C  [launcherS.exe+0x1b35]
C  [launcherS.exe+0x1c72]
C  [cygwin1.dll+0x5bc8]
C  [cygwin1.dll+0x5eb3]

Thanks in advance for any suggestion,
    Lapo and Alessandro

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