通过JNI调用时Java抛出Null异常，但从Java程序调用时可以工作

Question

I am using JNI to call Java methods from .jar library from external system. My problem is that everything works fine when I write simple Java program which uses the library, but when I am executing the same code via JNI the library throws Null exception when parsing Integer from String. I am sure that there is no problem in my JNI code, because I have a newer version of the library with the same interface which works fine via JNI. But unfortunately I have to use the older version because of compatibility issues with external system.

I think that the problem is in the way how jvm.dll creates VM - I am probably missing some argument which I should pass to jvm.dll when creating VM. Does anyone know where the problem could be?

I can't post my code, but I can explain it on example: - library version 1 contatins class Router with constructor Router(int i) - I don't have the code for this class - library version 2 conatins same class with same constructor - when I write simple program

import java.lang.reflect.*;

public class Basic
{
    public static void main(String[] args)
    {
        Router = new Router(10); 
    }
}

it works with both libraries.

When i run the same code with newer library 2 via JNI, it works too. But when I run the code via JNI with library 1, it crashes due to following internal exception

    Error message: System.Exception: JAVA Exception: java.lang.NullPointerException
at com.coda.core.types.TypeNumber.parseNumber(TypeNumber.java:403)
at com.coda.core.types.TypeInteger.parse(TypeInteger.java:123)
at com.coda.core.types.TypeInteger.parse(TypeInteger.java:137)
at com.coda.core.Options.setOption(Options.java:138)
at com.coda.core.Options.set(Options.java:85)
at com.coda.core.configuration.ConfigurationLoader.getConfiguration(ConfigurationLoader.java:144)
at com.coda.xml.Configuration.init(Configuration.java:453)
at com.coda.xml.Configuration.init(Configuration.java:370)
at com.coda.xml.router.AppServer.<init>(AppServer.java:250)
at com.coda.xml.router.Router.<init>(Router.java:122)

Answer 1

I have solved the problem. I had really mistake in parameters for JVM. The older library requires another jar library what I didn't knew. So I have added the library to class path and it works fine know. Really stupid exception with nothing saying message turned me to look for a problem in wrong way.

Thanks everybody for comments