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PLZ REPLY: JNI does NOT work under workbench! [message #445375]

Thu, 04 November 2004 15:10

Auerliano

Messages: 149
Registered: July 2009

Senior Member

Applying JNI (eg calling a c++ dll) to a java application using eclipse
works fine. But when the project is run as an eclipse workbench it doesn't
do anything. The worse thing is that the eclipse debugger is of no help to
trace the bug. Could it be possible that the eclipse class loader doesn't
work properly for JNI applications?

On the other hand, I understand that SWT uses JNI for the native look'n
feel. Seems I am missing something in running JNI under the workbench (or
generally RCP) mode. Any help is greatly appreciated!

-----------
In supporting my argument I refer you to an unsuccessful attempt of
importing the imagemagick C/C++ library via jmagick.jar to the eclipse
workbench:

http://coding.derkeiler.com/Archive/Java/comp.lang.java.prog rammer/2004-02/0247.html

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Re: PLZ REPLY: JNI does NOT work under workbench! [message #445394 is a reply to message #445375]

Thu, 04 November 2004 22:09

Christophe Cornu

Messages: 304
Registered: July 2009

Senior Member

Open a dos terminal:

set PATH=C:\Program Files\ImageMagick-5.5.7-Q8;%PATH%
eclipse

should work

Chris

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Re: PLZ REPLY: JNI does NOT work under workbench! [message #445396 is a reply to message #445394]

Thu, 04 November 2004 23:29

Auerliano

Messages: 149
Registered: July 2009

Senior Member

Chris,

The ImageMagick installer already puts the binary directory in the system
path. I have tried putting the dll's in different directories in the path
including windows\system32 and no luck!

Just try to run this minimal code as a java application in eclipse:

-----------------------------------------------
// Test.java
import magick.*;

public class Test {
static {
System.loadLibrary("JMagick");
}

public static void main(String[] args) throws MagickException {
ImageInfo info = new ImageInfo("c:/test/input.jpg");
}
}
// End of Test.java
-----------------------------------------------

This gives:
-----------------------------------------------
Exception in thread "main" java.lang.UnsatisfiedLinkError: no JMagick in
java.library.path
at java.lang.ClassLoader.loadLibrary(Unknown Source)
at java.lang.Runtime.loadLibrary0(Unknown Source)
at java.lang.System.loadLibrary(Unknown Source)
at magick.MagickLoader.<clinit>(MagickLoader.java:13)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Nativ e Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknow n Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Un known
Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at java.lang.Class.newInstance0(Unknown Source)
at java.lang.Class.newInstance(Unknown Source)
at magick.Magick.<clinit>(Magick.java:21)
at Test.main(Test.java:23)
-----------------------------------------------

Now this 'no JMagick in java.library.path' is driving me crazy!!
JMagick.jar, JMagick.dll and all the C-dll's *ARE* in a path in
'java.library.path'. I have verified it by
System.getroperty("java.library.path). What am I missing here? Do I have
to declare any native methods that I use in the java file? That is, if I,
say, use 'ImageInfo' function I have to declare something like:

public native void[?] ImageInfo(String arg0)

Thanks for the help.

Christophe Cornu wrote:

> Open a dos terminal:

> set PATH=C:Program FilesImageMagick-5.5.7-Q8;%PATH%
> eclipse

> should work

> Chris

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