JNI Call in java thread

Question

I made an example which works fine in the JAVA main
Thread, but crash in a new Thread, Why?
Is it possible to do something like that?
if no, how?
Main example:
same code but without thread
Thread example:
public class UserThread extends Threads{
private MyJNIObject myJNIObject;
public UserThread(){
try{
System.loadLibrary("myDLL.dll");
}catch(UnsatisfiedLinkError e){}
this.myJNIObject = new MyJNIObject();
public void run(){
this.myJNIObject.run();

Answer 1

I guess that you load myDLL.dll to implement Java native methods. To realize the problem you should know the mechanizm of this process.
1. Java native methods are implemented by java.lang.ClassLoader while this class is being loaded,
2. At this moment System.loadLibrary("myDLL.dll"); should be called, because java.lang.ClassLoader looks for export functions in DLLs already loaded to implement Java native methods,
3. You call System.loadLibrary("myDLL.dll"); in non-static block but in some method when native methods should be already implemented.
4. java.lang.ClassLoader cannot find DLL with proper export functions and thows an exception (it happens before the method with System.loadLibrary("myDLL.dll"); is called).
My recomendations:
- call System.loadLibrary("myDLL.dll"); in a static block of the class with native method implemented (or in some place you sure that JVM will know where to get functions while loading a class with native methods),
- put the same block in other classes which native methods will be implemented, because you do not know the order in which these classes will be loaded.