JNI and

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yshamama@magicsoftware.com - 14 Jun 2005 16:50 GMT

Hi all

I am using java from C++ using JNI calls
the JVM created when the C++ application is started
and destroyed just before it stop running

While my C++ app is running I am creating new class in java
and I want to use them using JNI calls
but the I can't found the class because its not in the classpath

what should I do ???

thanks

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Gordon Beaton - 14 Jun 2005 16:53 GMT

> While my C++ app is running I am creating new class in java and I
> want to use them using JNI calls but the I can't found the class
> because its not in the classpath

Specify a classpath argument when you create the JVM.

/gordon

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yshamama@magicsoftware.com - 15 Jun 2005 06:57 GMT

Hi

Thanks for your quick reply but my problem is that my classes is in a
jar file
and I don't have the location of the jar when I'm creating the JVM.
I get is location only after I alreay create the JVM.
I need a way to load the classes in that jar after I create the JVM
even if the jar file is not the classpath.

Thanks

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Chris Uppal - 15 Jun 2005 08:51 GMT

shamama@magicsoftware.com wrote:

> [..] but my problem is that my classes is in a jar file
> and I don't have the location of the jar when I'm creating the JVM.

Then your problem is /exactly/ the same as it would be if you were working in
Java directly, nothing whatever to do with JNI. The solution is also exactly
the same: create your own classloader (probably a java.net.URLClassLoader) and
use that to load code from the jar file.

(Actually you do have another option using JNI -- you could extract the
classfiles from the JAR file and then inject the bytecode into the JVM directly
using the DefineClass() function in JNI. Offhand, I can't think of any good
reason for wanting to do it that way, though.)

-- chris

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