Re: [Ikvm-developers] JNI problem with the lp_solve library...

[Jeroen F. <je...@su...>]

Hi Albert,

This is usually caused by running a 64 bit .NET executable and trying to load a 32 bit JNI library (or vice versa).

The horrible performance while debugging is a known issue.

Regards,
Jeroen

From: Albert Chan [mailto:Alb...@th...]
Sent: Wednesday, August 14, 2013 9:56
To: ikv...@li...
Subject: [Ikvm-developers] JNI problem with the lp_solve library...

Hi IKVM developer community,

Recently, my team started using ikvm 7.2 to convert a java library (produced by the Scala compiler) to a .NET dll. This Scala-java library has references to other 3rd party libraries. One of them is the lp_solve 5.5 library (http://lpsolve.sourceforge.net/5.5/) which uses JNI to talk to its native libraries. Both 32-bit and 64-bit versions of Java 6 were installed on our machine. While the java version of our library runs successfully in eclipse, the converted .NET binary exhibits a problem. When the logic executes to the point where methods from the lp_solve library are invoked, an exception is thrown with the following error:

The type initializer for 'lpsolve.LpSolve' threw an exception.
no lpsolve55j in java.library.path
   at java.lang.ClassLoader.loadLibrary(Class , String , Boolean )
   at java.lang.Runtime.loadLibrary0(Class , String )
   at java.lang.System.loadLibrary(String libname, CallerID )
   at lpsolve.LpSolve..cctor()

The lp_solve java stub library was include as one of the input jars to the ikvm conversion as follows:

ikvmc.exe -out:MyLib.dll -target:library MyLib.jar liblpsolve55j.jar <other dependent libraries...>

The following ikvm binaries were deployed to the same directory as our .NET executable:

ikvm-native-win32-x64.dll (deployed to C:\Windows\System32 as well)
ikvm-native-win32-x86.dll (deployed to C:\Windows\System32 as well)
IKVM.Runtime.JNI.dll
IKVM.Runtime.dll
IKVM.OpenJDK.Core.dll
IKVM.OpenJDK.Text.dll
IKVM.OpenJDK.Util.dll
IKVM.OpenJDK.XML.API.dll
IKVM.OpenJDK.XML.Parse.dll

The lp_solve libraries (lpsolve55j.dll, lpsolve55.dll) were deployed to the same directory as our .NET executable and:

C:\Windows\System32

On a separate note, up to the point where the converted .NET executable failed, the execution took 10 minutes (running in the Visual Studio debugger) while the Java version took about 1 minute. This seems to be a very significant performance difference as well (even with a debugger attached in .NET.)

Any help will be appreciated. Thanks in advance!


Albert